Blood Falls, in the Taylor Valley of Antarctica's remote McMurdo Dry Valleys, is a gushing stream of crimson-coloured saltwater flowing from the Taylor Glacier.
The bizarre colour of this saltwater is traced back about five million years, when the ocean flooded East Antarctica and created a salty inland lake. Over time, pristine saltwater from the ocean became trapped in a basin that was totally isolated from light, heat and oxygen. The saltwater became more and more concentrated in this basin, and is now said to be about three times saltier than the ocean, and too salty to freeze.
When this saline water trickles through small fissures in the ice, it reacts with oxygen in the air to create a brilliant, bloodlike hue.
The red cascade then spills onto the ice-covered surface of West Lake Bonney, earning its name, Blood Falls.
The phenomenon was first discovered in 1911 by Australian geologist Griffith Taylor, who first explored the valley that is now his namesake. At first, scientists thought the red colour was due to red algae.
But Blood Falls is not just an eye-popping natural wonder. Scientists believe it could also be the gateway to some crucial revelations about life in hostile environments.
Last year, a study on the bacteria in the saltwater suggested Antarctica could be awash with subterranean microbial life. Microbiologists found that the basin of saltwater covered a much bigger area than they initially thought.
"I've been studying Blood Falls for quite some time, and it's always been a mystery," lead author Jill Mikucki of the University of Tennessee told the Washington Post.
"We found, as expected, that there was something sourcing Blood Falls, and we found that these brines were more widespread than previously thought.
"They appear to connect these surface lakes that appear separated on the ground. That means there's the potential for a much more extensive sub-surface ecosystem, which I'm pretty jazzed about."
Scientists said the findings could provide new insights into how organisms adapt in extreme environments. And because the McMurdo Dry Valleys are similar to the surface of Mars or Jupiter's moon Europa, it could also help researchers understand how life could exist on other planets.
If you're keen to witness the bizarre spectacle for yourself, Blood Falls and McMurdo Dry Valley can be seen by helicopter from nearby Antarctic research stations or cruise ships visiting the Ross Sea.
