In Europe this summer, a drought and high-flying drone have revealed another "Stonehenge." The huge, ancient monument in Newgrange, Ireland, has remained hidden for centuries.

In the middle of a farmer's sprawling field of wheat, the monument is a series of dark markings in the shape of a perfect circle as wide as one and a half football fields. They're not extra terrestrial but they are a gateway to another world. A drone photographer captured the formation just over a week ago.

As Archeologist Stephen Davis explains, it's the remnants of a henge, a kind of ancient community center built around 5,000 years ago.

"In the Neolithic, it was absolutely hopping," Davis says. "There were loads of people here doing things."

Similar to England's famous Stonehenge, this Irish version was likely built using wood to create two fence-like structures. Over thousands of years they decomposed, leaving footprints of fertilized soil visible only when a heatwave wilts the crops around it.

"They knew what they were doing," Davis says. "And I suspect that if we try to do it today with the same tools that they were using, it would take an awful lot of time"

Newgrange, just 30 miles north from Dublin, is a Unesco World Heritage site known for its henges and other archeological treasures. And more treasures have been revealed as the entire region dries in record heat. Last week remnants of a ghost town and a World War II airfield were found.

"We know there are other secrets out there," Davis says.

Rain is in the forecast though, so those other secrets will likely remain hidden for now.