The reef was first recorded on a European chart in 1827 by Jules Dumont d'Urville on the first voyage of the sailing ship Astrolabe.
The name comes from an early Greek navigational instrument, the astrolabe, a precursor to the sextant.
Europeans called the area the Bay of Plenty for good reason and early Maori named it Tauranga, which is interpreted as a place to anchor in sheltered waters.
The port has grown to be the country's biggest and, with tourists drawn by the sun and sand, it is the economic lifeblood for a region nourished by the ocean.
But that was before Rena.
Day 1: The grounding
The early hours. It's the captain's birthday and stars are visible in a partly cloudy sky as the 236m Rena motors at full speed towards the port.
The cargo ship, which has visited often, doesn't get there this time. At 2.20am, the Filipino crew are jolted awake by a grinding and shuddering. Rena is well off course and has driven on to the reef at 17 knots.
The 21-year-old, 47,000-tonne box ship left Napier laden with 1386 containers 11 carrying hazardous substances, including ferrosilicon, which can ignite when in contact with water. The ship's fuel tanks the main four located low in the now-damaged hull - contain 1700 tonnes of fuel oil and 200 tonnes of diesel. The vessel settles on a 10-degree list in a slight swell.
It is the start of an unfolding disaster for a country whose attention has been fixed on the Rugby World Cup.
The Rena's trip up the east coast had not been without incident. The Torea, a 37,000-tonne tanker, made a 360-degree turn between midnight and 4am on October 2 near Napier after the Rena had sped by it. Torea's master will later tell Maritime NZ the turn was precautionary to give the Rena more sea room following its "overtaking manoeuvre". The incident becomes part of Maritime NZ's investigation into the grounding.
On Wednesday morning, the diving community is among the first to be alarmed. Would "Thrumo" have been broken by the impact? Thrumo is a large natural amphitheatre in an underwater cavern. It's just wonderful, says diver Shane Wasik. You drop down about 40 metres, then come up through the reef into a big circular amphitheatre and look around in awe as shafts of sunlight pierce the water.
But now there is a big, heavy ship on top of it. Divers have joked about wanting a new wreck to explore, but no one wants one at the expense of an environmental disaster.
Maritime NZ, which has an oil spill response plan, assesses the situation as a Tier 3 event, which means it is of national importance, and assumes responsibility.
A Maritime Incident Response Team is activated about 7am and a Maritime NZ safety inspector is on board the Rena from early morning until mid-afternoon. During the day, there are flyovers to check for leaks and Maritime NZ's marine pollution response service is mobilised, as is a team of trained spill responders.
In Auckland, Ronald Winstone offers the use of inflatable oil recovery barges. His company builds and sells these specialist barges around the world. He doesn't hear back.
Day 2: The bad oil
Confusion and mystery.
Rena is flying a Liberian flag. She is one of 51 ships listed by the Greek firm Costamare Shipping, parent of Liberia-based Daina Shipping, but is under charter to the Mediterranean Shipping Company.
Liberia, in West Africa, is one of the countries that provide what are referred to as "flags of convenience". They have lower compliance costs and are a cheap option for ship owners. Registration in these countries can also mean there are fewer liabilities under international shipping conventions.
The worst of the flag-of-convenience nations, says Victoria University marine law specialist Joanna Mossop, can be quite lax about compliance issues, but Liberia is not one of the worst.
In Tauranga, locals are concerned, but many people around the country still have eyes only for the coming weekend's knockout clashes in the rugby.
The first of the salvage team, who had arrived the previous night, quickly realise they face some big issues. Most of the pipes between the fuel tanks run along the keel - and many are damaged. This would later require heavy hoses to be laid across the deck to transfer oil.
An aerial observation has confirmed oil leakage overnight - a light slick can be seen stretching about 2km in a narrow ribbon.
The salvors find that No 3 starboard tank (one of the four main fuel tanks) is leaking oil into the hull which is sloshing around and escaping into the sea.
The oil spill response team conduct a dispersant field test - dispersants are chemicals to break down the oil - and Corexit 900 is then used, which for greenies will prove a controversial choice.
A wildlife response is also launched after four dead birds are found in the water near the boat and a bird cleaning and rehabilitation centre is set up with a base at Motiti Island.
The ship's owner appoints salvage experts Svitzer and their staff leave Holland for Tauranga. On board, the Rena's equipment is assessed as teams work out how to get the oil off.
In the water, divers are trying to assess the fuel tanks and how stable the ship is on the reef.
No one wants a big oil spill. Motiti Island is only four nautical miles away and the bay coastline only 12.
The No 3 tank is nearer the bow and thus most vulnerable. The goal is to get the oil off, but more pressing is the need to pump it from the most vulnerable tanks into safe ones and to make all of them as watertight as possible in case the ship breaks up.
The fuel barge Awanuia is hired and tugs and navy ships are brought in.
Day 3: Initial response
Still no information on how the boat hit the reef, but during the day it emerges three crew members on duty at the time of the grounding are being spoken to.
Corexit is again sprayed, though it has not been as effective as hoped and Maritime NZ prepares to collect heavy fuel oil that has spilled into the sea overnight.
Only a relatively small amount has escaped from damaged pipes but from the air it looks dramatic. Black oil can be seen spilling from the ship and there is a thinner, lighter-coloured sheen trailing northward for about 6km.
On land, a sinking feeling. Patients begin to arrive at the wildlife centre at Mt Maunganui. A little blue penguin from Papamoa Beach is in trouble and another from Little Waihi, plus two shags found on Motiti Island.
Images of birds struggling to move with feathers covered in sticky black oil are shocking, not least for Forest and Bird - it's breeding season for a variety of birds which will be feeding in the waters around the ship.
Resources, however, are pouring in from overseas to assist what is now a 100-strong Maritime NZ team, and dozens of volunteers are helping, combing beaches on quad bikes for any sign of oil.
So far there is none but disquiet is growing. The weather has remained fine but not much can be seen being done. Calls mount for the Government to take control of the operation.
The lead minister is Steven Joyce (transport), who is being closely briefed. He is flown over the ship and reports seeing whitecaps, indicating the weather is deteriorating.
An offshore boom barrier to ring-fence the oil - measuring about 1250m - is on its way from Australia along with three heavy skimmers to scoop oil from the water.
But why, people ask, have not booms already been placed around the boat?
Joyce later says they work only in very calm waters. He is unsure whether booms could have been put out on Thursday but it was too choppy by Friday.
"They have a menu of options in trying to contain an oil slick. The sea-based ones are booms or chemical dispersants. The booms were not suitable on the Friday or Saturday so they used dispersants.
"All these options are limited and that is something that surprises people and surprised me too. The reality is booms and chemical dispersants are only ever moderately successful.
"The jury is still out on how effective the dispersant used has been. It depends on the type of oil, type of dispersant, the conditions and the age of the oil on the sea. It is only really suitable when you have oil fresh in the sea because as it weathers the chemical dispersants don't work.
"The reality is that only about 10 per cent of the oil in these situations is at best mopped up at sea. The rest is dispersed by the ocean or it comes ashore."
Tauranga man Scott Hutchison, a specialist who was involved with the BP oil disaster in the Gulf of Mexico last year, questions why a major port does not seem to have adequate equipment on hand, telling the Herald there is a global problem of big commercial vessels not equipped to deal with oil spills.
Tauranga Mayor Stuart Crosby says the spill is a "surreal and eerie sight" and Environmental Defence Society chairman Gary Taylor worries the incident is "inexorably moving into a full-scale environmental disaster".
"We are not convinced by what we have seen so far that Maritime New Zealand has the situation under control," Taylor says.
Day 4: Signs of hope
Optimism. An observation flight finds oil seems to have stopped flowing.
Dispersant is put on hold until any more thick patches of oil are seen.
Specialists from around New Zealand and Australia continue to arrive - there are now close to 200 people in the response team, including staff from the regional council, Department of Conservation, Massey University and other agencies.
The Defence Force has joined the command centre and four military vessels are deployed - the Rotoiti, Taupo and Manawanui arrive and the Endeavour is expected on Monday.
Another 500 Defence Force staff are put on standby and the Ports of Auckland tug Waka Kume arrives, and later the Awanuia.
Svitzer staff have also arrived and take charge along with Maritime NZ. Joyce says later that he understands Svitzer is one of the best - if not the best - in the business.
Beaches are scoured for affected animals. The tally is seven little blue penguins and two shags with oil coverage of 30 to 100 per cent.
The response team receives technical advice and support from Britain, Australia and Singapore and national and international offers of assistance and equipment are coming in.
Day 5: Reinforcements
Oil is expected to hit the coastline - but good progress is being made, says Maritime New Zealand.
The Awanuia is berthed alongside the Rena and the salvage team is pumping oil from the damaged tank to a tank nearer the rear of the boat so it can then be pumped on to the Awanuia, which can can hold 3000 tonnes of oil and is designed to refuel ships at sea.
The top priority is to remove the oil from the ship, then the containers, then finally remove the Rena from the reef. Similar tasks overseas have taken months.
But the weather is expected to turn, so containers are lashed more tightly. Specialists on board use sensors to give advance warning if the structure is becoming too stressed.
Covers are made to seal vents so no oil can escape.
A Hercules C130 is diverted from Australia to bring more equipment, an Iroquois is stationed at Tauranga, and two ocean-going barges, the Northern Quest and Phoenix, will help clean up oil in the water.
HMNZS Endeavour arrives in the evening to be used as a command platform, and at 8.30pm pumping of oil to the Awanuia finally begins.
But it soon stops due to rough seas and safety concerns.
Only 10 tonnes is transferred and the Awanuia returns to port for repairs after it crashes against the Rena.
The All Blacks beat Argentina and Australia hold out South Africa.
Day 6: Oily beaches
Ugly black globules of oil lie in splotches on the popular beaches at Mt Maunganui and Papamoa. Up close, the thick globs appear as a nasty jet-black jelly, and foul fumes hang in the air.
Locals mill around, many speechless. A little girl, her blonde hair buffeted in the heavy, oily wind, crouches and squints at the spots, which she tries not to get on her gumboots. Iwi leader Neil Ti Kane kneels and curses officials - where are they?
Maritime NZ says people should stay off the beaches and not touch the oil or try to clean it up, and warns more will come.
Collection of shellfish, sediment and water for sampling is taking place and sensitive sites are also monitored.
A bid is made to lay a boom to protect Maketu Estuary but strong currents and surges make this difficult.
No more oiled wildlife is reported but searching continues and the nine birds treated so far have made a good recovery.
Thirty-six salvors and crew are on board the Rena and the air force has flown in more crew for the Awanuia, but bad weather hampers oil collection.
All vents on the Rena are sealed and there are no obvious signs of the vessel warping.
It's now estimated 100 tonnes of oil has leaked into the duct keel and teams work around the clock. Locals go to bed nervous about what tomorrow will bring.
Day 7: Stormy weather
Morning radio reports the bad weather overnight has actually been good because the ship has righted itself and looks more stable.
But there is a fresh oil leak and the weather is terrible. By 10am, news breaks of a mayday call from the Rena for an Iroquois to evacuate everyone on board, yet almost as quickly a spokesman for Maritime NZ says the mayday call is a "standard precautionary measure" and that the ship is not breaking up.
Later, a maritime union official says this is rubbish; the people on board would have been terrified.
The crew are taken off and a naval rating is hurt in the huge seas (3m to 4m swells) and 20- to 25-knot winds.
The containers are all intact, but by now locals are boiling with frustration and fear for their beaches and the wildlife.
Many give voice to their anger on social media. Amiria Marcia: "It seems our beach is our problem. We are breathing in the toxic crap regardless. May as well stop talking about it and just get rid of it; maybe dump it on the council steps. Maybe then they will care?"
Al Fleming from Forest and Bird spells out what is at stake. There are estimated to be 10,000 grey-faced petrels, thousands of diving petrels, white-faced storm petrels and fluttering shearwaters breeding on nearby islands, including colonies on islands off the Coromandel Peninsula and feeding in the Bay of Plenty.
A colony of several thousand gannets is on White Island and 200 to 300 little blue penguins are estimated to be living along the coast in the vicinity of the oil spill.
It's feared that any seabirds that breed in burrows and get oil on their feathers could carry that into nests and harm their chicks.
Shorebirds such as endangered New Zealand dotterels, and oystercatchers and white-fronted terns, that are starting to nest on sandy beaches just above the high tide mark are also at risk - spring tides, storm surges and low-pressure systems could combine to bring the oil higher up the beach and smother eggs and chicks.
Other migratory birds such as godwits and red knots are on their way to New Zealand, fur seals are moulting on headlands, islands and beaches and travelling whales are also at risk - sticky oil can cling to the baleen plates of filter-feeding whales. Plus there's the potentially disastrous danger to finfish, shellfish, crustaceans, filter feeders and other seafloor life.
"Eventually the oil will accumulate throughout the food chain," says Fleming.
In the afternoon, confirmation of fears. The Government admits the spill is now our worst maritime environmental disaster.
Environment Minister Nick Smith fronts in Tauranga and says oil has been pouring out of the boat at five times the rate it had in the days after the grounding, and warns people to expect the beaches to be blackened - possibly for weeks.
Between 130 and 350 tonnes have leaked into the sea this morning, up from the previous estimate of between 20 and 30 tonnes.
Oil is spewing from a main fuel tank on the vessel and Smith promises the Government will hold to account those responsible.
The public are warned again to stay off the beaches and to keep pets away, and at night locals fill an auditorium at Tauranga Boys' College and cram the side entrances for a meeting with officials.
Straight-talking Maritime NZ boss Catherine Taylor, a former accountant, breaks most of the bad news. Slides of the ship's blueprints are shown and the audience is told a duct keel - a compartment running the length of the bottom of the ship which houses piping and electrical equipment - was breached against the reef and is to blame for the spill.
There will be oil in the pipelines, Taylor says, and there is oil leaking out of that part of the keel.
Nick Smith is there too. He looks wary.
"I can think of no excusable reason as to why, on a perfectly calm day, a 47,000-tonne vessel should [slam] into a reef that is well-documented, known by everybody, in this day and age with GPS and every other sophistication."
Questions pour from the audience.
Why so long for pumping to begin? Why is Corexit being used when it is banned by some countries? Why have iwi not been involved?
On and on the questions go - why were there no booms, how could the Government ensure the same will not happen with deep-sea oil drilling, what will the next two years look like for the Bay of Plenty?
Answers include: There's oil. We don't know how much.
The ship crashed. We don't know how.
We want to get the salvors back on board. We don't know when.
The ship will probably sink. We don't know when.
The ship owners will pay around $14 million. We don't know how much the taxpayer will.
One thing is certain - more oil will come.
Day 8: Cargo overboard
From the air, army Unimogs look like toys amid the black ooze stretching across the long strip of beach between Mt Maunganui and Papamoa.
Out to sea, the Rena looks pathetic, hunched against the reef with oil surging from her gut.
Around her, it looks like a giant has upended a rubbish transfer station into the blue water - now a mess of flotsam, bobbing containers and splotches of greenish oil floating around a huge, silvery oil slick trailing ominously towards the mainland.
Motiti Island is ringed with green gunk and black beaches and the odd container is crumpled against the rocky shores like a crushed Coke can.
Overnight, 70 containers crashed into the sea in the bad weather.
Shipping has been rerouted because of the danger the floaters pose and it's likely more will fall off into a raging sea.
The day goes from bad to worse.
The captain is arrested in the morning and appears in court charged with operating a vessel in a manner causing unnecessary danger or risk, and in the evening the second officer is also arrested.
This big news is eclipsed by the fact the boat is in even more trouble. During the day it is revealed a big crack has appeared in the side, in the number three cargo hold.
This is caused by the stern remaining afloat and shifting with the waves while the bow sits rigid on the reef.
It is feared the stern could break away. The salvage team has three tugs on hand to either hold that part of the boat on the reef while further effort is made to remove the oil, or to tow the stern to shallow water where the oil can be removed.
On shore, people have ignored the warnings to stay away. In the past few days they have scraped up contaminated sand, leaving little plastic bags of the stuff dotted on beaches.
Official clean-up teams also toil on the beaches and four vessels keep guard in Tauranga Harbour in case oil arrives there.
There is talk of evacuating dotterels, and a wandering albatross is found dead, so covered in oil it can barely be identified.
The death toll is rising fast. From 53 dead birds and 17 oiled birds as of Tuesday night, there are now reports that more than 200 have died.
They are mostly diving petrels and pied shags and though some are poisoned from ingesting oil, many are freezing to death because the oil blocks their ability to insulate themselves against the cold.
Workers brush and bathe the birds they can, but then face the problem of having no safe habitation to send them back to. But at least Costamare (the ship's owners, who have been very quiet) have approved care and housing for at least 500 birds.
Fur seal pups have been removed as a precaution; many others are in jeopardy.
Day 9: Hope fades
Dead, oiled birds are lined up in rows. An oily fur seal features on the TV news, slipping on the oily rocks.
Eighty-eight containers are now embedded in the sand or floating in the sea, though some may have sunk.
Debris is strewn far and wide, including thousands of meat patties scattered on Papamoa Beach.
The weather has improved enough, though, for three of the salvage team to be winched back on board, and the Awanuia is back but still there is no pumping of oil.
More than 2000 people have volunteered to help with the clean-up and some are being trained but others are asked to be patient.
Eleven of the Filipino crew are sent home and local Filipinos are feeling a backlash, copping the blame from an angry public. And in the afternoon, finally there is an apology from the ship's owners. Obviously something went very wrong and Costamare is deeply sorry, says managing director Diamantis Manos.
The situation is heart-breaking, says Port of Tauranga chief executive Mark Cairns.
Says Svitzer spokesman Matthew Watson: "There is not very much room for optimism."
Day 10: Heavy toll
The weather is finally kinder but oil has now washed up on 60km of coastline and extends almost to Whakatane.
The boat is on a 21-degree list and work has begun to build platforms to help get the rest of the fuel off.
Minister Joyce says an estimated 1000 tonnes is aboard most of it in the port No 5 tank, which is thought to be secure.
Strong winds are forecast and a westerly wind is expected to get up to 25 to 30 knots.
A container of water-soluble alkylsuphonic liquid is missing from the boat, though Maritime NZ says it is not considered a significant health risk.
The toll stands at 1000 dead birds and there is no pumping of oil.
The Prime Minister meets angry residents at Papamoa College and later at the beachside community's surf club.
John Key tries to put the crisis simply to the 200 people packed into the college hall by answering his own questions.
"Why didn't you start pumping the oil straight away? You're a bunch of bozos. You should have been able to work out the weather was going to change. Why didn't you get it off the ship?" he says.
"The answer to that is, if we had just gone on to the ship, turned on the taps and started pumping, it would have spewed oil into the sea."
Sparks threaten to fly when one Papamoa man who introduces himself as Peter stands up and begins walking towards Key, demanding to know whether the Port of Tauranga is going to expand or if the Government backs oil drilling off the East Cape.
One of Key's diplomatic protection squad police officers approaches the man as he edges closer clutching a wooden cane with one hand in the air.
Others quiz Key on the use of dispersants, where the oil is being trucked to and whether affected businessmen will be compensated.
Another Papamoa man attempts to get into a debate with Key about who is responsible for ensuring ships take the correct course.
"What's Maritime New Zealand doing about this? Why are we in the position we are in today?"
Several police officers keep watch around the college's sports field as Key walks from the meeting to a waiting Seasprite helicopter to fly over the stricken ship.
Later, at Papamoa beach, Key chats and shakes hands with members of the clean-up team, before speaking to a gathering of about 200 people from the top of a sand dune.
But in the face of a chorus of criticism and questions, the Government says the response to the Rena crisis is as good as the complex circumstances allow.
It says damage to the ship's fuel lines meant pumping off oil could not start until day five and sea conditions were not suitable for protective booms to be laid to contain escaping oil near the ship.
The future:
Around the country heads are being scratched as to how this could happen and how on Earth we would cope with an even bigger spill from offshore drilling, an oil tanker or a transporter laden with uranium oxides nuclear fuel material which pass through Tauranga, Auckland and Nelson.
We wouldn't, says the man who offered the inflatable oil recovery barges, Ronald Winstone.
But no country our size would. The rest of the world would come to the rescue, just as we helped out in the Gulf of Mexico oil spill last year.
The Environmental Defence Society has already called for a royal commission of inquiry. New Zealand has 19,000km of coastline and our oceans are rich in biodiversity - they define who we are as a nation, says chairman Gary Taylor.
"We must ensure nothing like this can happen again."
