Peering underneath a gigantic rock that seemed out of place, one farmer in Orkney, Scotland, would never in his wildest dreams expect he was about to make history.
He probably expected to find grass or mud -- not a 5,000-year-old treasure. Its age makes it one of the greatest historical discoveries in the world.
As if it were a portal into another world, the stone was hiding a lost, ancient city: Skara Brae, one of Great Britain's oldest settlements, AWM reports.
It's so ancient, historians say it could even be older than the Egyptian pyramids.
"Long before Stonehenge or even the Egyptian pyramids were built, Skara Brae was a thriving village," according to Historic Environment Scotland.
Initially, the farmer uncovered only a house buried underground.
As he explored further, however, it became clear there was more to discover: an entire underground city.
What's more, the eight houses that were still remaining were well-preserved.
"Skara Brae is remarkable because of its age, and even more so for the quality of its preservation," says Historic Environment Scotland. "Its structures survive in impressive condition -- as does, incredibly, the furniture in the village houses. Nowhere else in Western Europe can we see such rich evidence of how our remote ancestors actually lived."
The ancient dwellings were large enough, experts say, to house anywhere between 50-100 people each.
Houses were connected via underground tunnels, offering massive insight into the ancient lifestyle.
“The villagers were real neighbors living cheek by jowl, their houses connected by walled, sometimes decorated, alleyways,” said Simon Schama, a professor at Columbia University, Live Science reports. “It’s not too much of a stretch to imagine gossip traveling down those alleyways after a hearty seafood supper.”
What makes the ancient city even more unique is its faith to community and equality, Newsner reports.
Archeologists say they believe the fact the houses look similar, among other city features, reveal an equal, family-oriented society, without an authoritarian leadership.
Since its discovery, thousands have flocked to Skara Brae.
But some experts worry about its fate. Some believe climate change may finally be the last nail in the coffin for this old city that's lasted 5 millennia.
"In the century ahead, Skara Brae, like other coastal sites around the world, may be threatened by rising sea levels caused by global warming, a modern-day problem that threatens a site that has withstood 5,000 years of time," writes Owen Jarus for Live Science.