A previously unknown prehistoric 'lost world" has been hiding on Earth 12,000 feet above sea level

Deep in unexplored lagoons unlock the answers to a prehistoric world we’ve never studied before.

Some of the earliest evidence of life on Earth exists in stromatolites - ancient rocks that date to three-quarters of the way back to the origins of the solar system.

The rocks are built by colonies of microscopic organisms known as cyanobacteria and can grow to more than 3.3 ft high.

There are lots of ancient stromatolites in Shark Bay in Australia (Koradi/Getty)

The most famous examples of these prehistoric rocks are in Shark Bay, Western Australia, where their spectacular shoreline has given the region World Heritage status.

There, the stromatolites are a glimpse into what marine ecosystems would have looked like three billion years ago.

But while Shark Bay might be a hotspot for tourists to visit these ancient organisms, there is another place located in Puna de Atacama, northern Chile where scientists made an exciting discovery.

In a remote location of the region, more than 12,000 ft above sea level, researchers have uncovered even more interesting stromatolites.

The primal rocks inhabit salty lagoons that are nearly impossible for scientists to access, which is how they went unnoticed for so long.

Researchers found a prehistoric 'lost world' 12,000 ft above sea level (Brian Hynek/University of Colorado Boulder)

It was so difficult to reach that Dr Mariá Farías of PUNABIO Environmental Consulting and Professor Brian Hynek of Colorado University, Boulder, embarked on a nine-hour drive on dirt roads before hiking up to the lagoons.

Hynek said: “In some places, we were sinking up to our knees in salt slush.”

But it was all worth it in the end as the professor added: “This lagoon could be one of the best modern examples of the earliest signs of life on Earth. It’s unlike anything I’ve ever seen or, really, like anything any scientist has ever seen.”

“It’s just amazing that you can still find undocumented things like that on our planet.”

The pair found 12 lagoons across 25 acres where Hynek saw living stromatolites larger than any he’d ever seen - as some were up to 15 ft wide.

The ancient rocks can only survive in a rare environment (Brian Hynek/University of Colorado Boulder)

The environment they're in, which includes very saline and acidic water and sunlight that has not been filtered by the lower atmosphere, is likely a lot like early Earth, according to Hynek.

And studying these rocks could help us to better understand extraterrestrial life too.

Hynek added: “If life ever evolved on Mars to the level of fossils, it would have been like this. Understanding these modern communities on Earth could inform us about what we should look for as we search for similar features in the Martian rocks.”

The oldest stromatolite fossils are 3.5 billion years old but today they are vulnerable to other species who feed on them.

Now, they only survive in rare environments on Earth where other life cannot.