These stone gods and kings feel somehow more precious than their counterparts in the treasure houses of other equally proud countries. They are survivors of Year Zero, the Khmer Rouge's attempt to erase history, proof of the Cambodian ability to create and preserve beauty through the destruction that engulfed their country .
In one room is a statue of the meditating Buddha, perhaps from the 13th century. A little enclosure has been created for it, with a table for offerings, and on the sides of its concrete base the "four noble truths" of Buddhism picked out in river pebbles: you should know suffering; you should abandon origins; you should attain cessation; and (the odd one out, in French) "l'ignorance est l'ennemi de la vie".
That is not the usual phrasing of the "fourth truth", an injunction to follow the path of Buddhist teaching. "Ignorance is the enemy of life" sounds like the anguished cry of a museum curator, a warning from someone alive in the old colonial days when French was widely spoken. Whatever you do, don't smash the past. Don't forget.
Here in Phnom Penh, it's hard not to read a terrible sadness into these Buddhist instructions for transcending the pain of existence.
Across town is a former school known as Tuol Sleng, a cluster of rundown concrete buildings around an open yard. This was once S-21, an interrogation centre where Khmer Rouge cadres, many no more than children, used torture to extract insane, florid confessions from their prisoners, who were then driven out of the city to the killing fields. An estimated 17,000 people passed through this place. There were seven survivors.
Tuol Sleng is almost unbearable. Not because of the classrooms partitioned by crudely built brick walls into tiny cells. Not even because of the display of shackles and torture instruments, or the lurid paintings done by one of the survivors. The hardest part is seeing the faces of the victims.
Everyone brought to S-21 had their picture taken, numbers around their necks, clamped into a device to keep their heads still for the camera's shutter. There are rooms of 10-by-eights of dead people, men, women and children, even tiny babies, "discarded" (in the jargon of the interrogators) because of their perceived threat to the paranoid members of the Central Committee.
During the three years, eight months and 20 days of Khmer Rouge rule, around 1.5 million people died, out of a total population of 9 million, an event one writer has described as "auto-genocide".
On the faces of the prisoners of S-21 you see fear, confusion and defiance, but most wear an expression of blank disengagement, a resignation that seems to go beyond the effects of tiredness and hunger, an acceptance that the world they will soon be leaving is filled with horror, and that nothing they could think or do would ever make it change.
Legend has it that when the Khmer Rouge entered Phnom Penh in April 1975, journalists watching from the balcony of the Foreign Correspondents Club left in such a hurry that the people who opened the boarded-up building years later found cameras on the floor, complete with undeveloped images of the fighting.
It's now a restaurant, full of tourists eating club sandwiches and reading their Lonely Planet guides, but it still has a view over the Tonle Sap river and is as good a spot as any to watch today's street life, the vendors pushing carts, cyclo drivers hustling for customers, beefy white men and waif-like Cambodian women getting in and out of tuk-tuks.
A dry local joke about the club is that it's the only place where the city's many NGO workers have to grit their teeth and make conversation with so-called "sexpats".
Around the country, beside posters warning of the dangers of bird flu and landmines (the bird flu one has a picture of a mother scolding her little boy for playing with a dead chicken), you see an image of smiling children, part of a campaign against trafficking and child prostitution.
A second dry local joke has it that Cambodians should thank Gary Glitter for this, the issue having shot up the international funding agenda after the huge publicity surrounding the glam-rocker's deportation in 2003.
Today's Phnom Penh has come a long way from the haunted, empty place of 1975, when the Khmer Rouge drove its entire population into the countryside to grow rice. It's a pleasant city, with bustling markets, elegant colonial-era boulevards, good bars, some startling modernist architecture, and an ease and friendliness that will no doubt soon make it one of the most popular destinations in Asia.
The incomparable temples at Angkor have long drawn large numbers of tourists, but for years, while the guerrillas were a lurking presence in rural areas and the US and Britain played cold war politics here - helping the genocidal Pol Pot against the Vietnamese-backed government - Angkor was the only place in the country where many foreigners felt safe.
Since Pol Pot's death in 1998, security has returned. Little by little, the minefields are being cleared and the shattered infrastructure rebuilt.
Places that were hard to visit a year or two ago are now accessible, thanks to new roads. Elegant French hotels like Le Royal have reopened, and as Cambodia is plugged back into the global economy, speculators are moving in.
Vietnamese and Korean investors are snapping up beaches and ruined villas. Australian mining companies are at work in the forests. In another five years, much of the country will look very different.
Drive out of Phnom Penh and you get a sense of rapid change. Garment factories line the road, which is thronged with motorcycles pulling flat-bed trailers packed with workers, mostly peasants flooding in from the countryside to earn between $30 and $80 a month (the official minimum wage is $45).
In the Russian Market you can find branded clothing, some obvious fakes, others the genuine article. Further into the countryside, boards bearing mobile phone numbers are nailed to trees. The Khmer Rouge abolished property and destroyed most records. Until recently all land belonged to the state. Now it's a free-for-all. Anyone who can enforce a claim stands a chance of getting rich.
One place that won't stay the same for long is the abandoned hill station of Bokor. Built in the 1920s, it was to Indochina's French elite what Simla was to the British raj, a retreat from the summer heat, a place for intrigue and love affairs. Later it became a Khmer Rouge stronghold: much of the mountain is still heavily mined.
To get to the top, you make a bone-shaking 30km climb by dirt bike or four-wheel drive.
Bokor is dominated by the melancholy shell of the old casino, which stands on the edge of a cloudy abyss, into which more than one ruined gambler must have thrown himself before war closed the "Bokor Palace". Now its bullet-riddled facade is crumbling and the grand hall is a palimpsest of graffiti, mostly the names of European backpackers.
Sokimex, the government-linked petroleum company which also owns the ticket concession for Angkor, is reported to have tabled a US$100 million plan to build a new road, a 300-room hotel, a golf course and 100 luxury villas at Bokor.
While there's no reason to expect Cambodians to live in the rubble of a painful war, Bokor's gloomy beauty will dissipate when it becomes a 21st-century resort, buzzing with the sounds of electric golf carts and credit card machines.
Similar rumours hang around the south coast resort of Kep. It takes half an hour on a narrow diesel-engined boat to reach Koh Tansay, where the fishermen have heard that their island, on which the French built a "motel" (there are no roads) and the Khmer Rouge a re-education camp, is to be the site of a new resort.
They do pretty good business, fishing for the famous local crab, frying it with black pepper and serving it to people like me, who come to swim in the lagoon, drink beer and watch them mend their nets. They worry, with good reason, that they won't be able to prove this place is theirs, if someone "high ranking" tries to take it.
The night I sleep on the island an electrical storm passes over, sending an hour of heavy rain and intense sheet-lightning, inverting the night sky. The boats have come in and the crew are watching TV in a hut. It must be an old film. The voice is the one I've been searching for in markets, the king of Khmer pop, Sin Sisamouth, who like so many other "new citizens", urbanites whom Pol Pot wished to reprogramme with the values of the peasantry, disappeared into the black hole of the 1970s. Sin liked the twist and surf guitar. Another Cambodian ghost story.
Some things won't change in the next Cambodia: temples, rice. I see Angkor over Khmer new year, when it's swarming with families scrambling up the steep stairs to the sanctuary and taking snapshots.
A few days later I'm scudding on a motor boat down a long irrigation canal flanked by rice paddies. Men and women thresh rice and pack it into sacks. Sullen Vietnamese traders wait in boats to carry it over the border.
Our destination is Phnom Da, a hill with a simple laterite temple, one corner scooped out by a rocket. "B40," says Chamroeun, my guide, who knows more than he wants to about munitions.
In 1998, after the mysterious death and ignominious truck-tyre cremation of Pol Pot, the last Khmer Rouge cadres, under "Brother number five", the one-legged general Ta Mok, made a final stand at an ancient temple complex called Prasat Preah Vihar.
Dedicated to Shiva, the destroyer of the Hindu pantheon, it was built between the ninth and 12th centuries by seven successive Khmer monarchs, whose masons hewed out stone stairs and gopuras from a breathtaking peak that looks out over the densely forested mountain range marking the border with Thailand.
Ever since, pilgrims have made their way up, through five successive levels, to the sanctuary at the top. Ta Mok's troops mined the approaches, dug trenches and mounted guns. After a few months they surrendered. The general, already 80 years old, died of natural causes last year, while awaiting his endlessly deferred genocide trial.
Now young men laugh and chat and greet their friends, souvenir-sellers are packing up and heading back down to their village. Everyone seems relaxed and optimistic.
At sunrise I wake in my tent and climb up again to look at the view. A picnicking family have had the same idea. Everyone seems to be looking forward to the new day.
- OBSERVER
