We humans have spread to every corner of the globe, felling rainforests, raising cities from marshland and releasing smoke into our skies. But is there a place on Earth that would be exactly the same if humans had never arrived?
That’s a question my producer, Florian Bohr, and I wanted to answer for our Radio 4 series Looking for No Man’s Land.
- It’s the size of Oregon, contains 25,000 lakes and lies 100km north of the Arctic Circle – and it's only accessible by helicopter or boat
- This giant underwater 'cloud' lies at the bottom of a 60m-deep sinkhole. It's concealing something ghostly
In the past half-century, almost the entire surface of our planet has warmed, largely thanks to gases emitted by humans. We’ve altered the temperature and chemical makeup of Earth’s surface – so we needed to look down.
Could there be a pristine place in our seas? In 2025, Scottish marine biologist Alan Jamison visited the second deepest point on the planet: the Tonga Trench.
- It’s so deep it could swallow 24 Empire State Buildings stacked one on top of the other – and they’d still be submerged
- How deep is the deepest part of the ocean?
Astonishingly, at nearly 11,000m down, he found a plastic cement bag. But it’s not big pieces of plastic that most concern him.
Jamison has studied microplastics in crustaceans that live deep in the Pacific Ocean, and in the least polluted place he sampled, three out of four animals had microplastics in their gut.
Even deep-sea creatures depend on food from above, a world we’ve irreversibly altered. With the planet’s surface and our oceans off the cards, we needed to get creative.
There’s one creature that acts as a powerful clue for unchanged environments: olms – long, skinny salamanders with ghostly pink skin.
Olms can live for more than a century but they’re incredibly delicate and if their environment changes they often don’t survive. They can be found in cave systems across eastern Europe, but they’re struggling.
- Meet the mysterious olm – a weird and extremely rare cave-dwelling predator nicknamed the 'human fish'
- It's 3 million years old, the size of Vikos Gorge and is home to one of the world's weirdest animals
The caves are polluted – fertilisers, pesticides and even sewage are seeping down from above. On the rare occasion that you do find a cave full of thriving olms, there’s still a problem, as the water they live in comes from rainwater, which humans have chemically altered.
But what about caves that don’t fill with rainwater? Hypogenic caves instead form from water rising up, such as Lechuguilla Cave in New Mexico.
Cave microbiologist Hazel Barton has explored Lechuguilla’s passageways and has noticed something remarkable. The cave breathes.
As weather changes on the surface, the shifts in pressure force air into the cave – air we know humans have altered. But there are likely hundreds of hypogenic caves across the region that are yet to be discovered by humans because they don’t have entrances.
Without entrances, the caves can’t ‘breathe’ and are totally unaffected by humans.
There could therefore be thousands of kilometres of pristine passageways hiding beneath our feet – not just in New Mexico, but all over the world.
Top image: the Cuevas del Drach in Mallorca. Credit: Francesco Riccardo Iacomino/Getty Images
