Drought and Drone Reveal ‘Once-in-a-Lifetime’ Signs of Ancient Henge in Ireland

It took an unusually brutal drought for signs of a 5,000-year-old monument to suddenly appear in an Irish field, as if they had been written into the landscape in invisible ink.

On Monday, Anthony Murphy, an author and photographer, sent a camera-enabled drone high above the Brú na Bóinne archaeological landscape, a UNESCO World Heritage Site about 30 miles north of Dublin. He suspected that recent dry conditions might reveal evidence that a henge — a man-made enclosure from thousands of years ago thought to serve as a gathering place — had once been there.

What he and a friend saw in the images shocked him: a series of discolorations in the farmland, caused by differences in soil, spread about 150 meters wide in a perfectly circular pattern. He had flown the drone over the same field many times before and never saw a hint of what was now perfectly clear, he said.

“We knew fairly quickly that this was something that hadn’t been seen before, and I think we both knew it was something very special,” Murphy, who runs the Mythical Ireland website, said in an interview.

It has been more than 40 days since the Dublin area has had significant rainfall, and the dearth of water had left the field, which is on privately owned land, scorched by the sun.

But archaeologists say the soil where people of the Neolithic age likely put large timber posts can hold more residual moisture, allowing it to better cope with drought conditions and display a healthier shade of green. The timber would have rotted away over time, but the soil would maintain its differences.

The finding electrified archaeologists, who already considered the area of great historical importance. There are several other henges in the area, and the new one was found a few hundred meters south of the Great Passage Tomb of Newgrange, one of the largest draws for thousands of tourists per year.

Michael MacDonagh, chief archaeologist for Ireland’s National Monuments Service, called it a “once-in-a-lifetime” find that would “add greatly to our knowledge of this magical archaeological landscape.” The pattern was about 150 meters wide, potentially big enough to hold a few thousand people, and estimated to be 5,000 years old.

“There’s a whole generation of archaeologists who have never seen a site emerge with such clarity out of the ground like this,” he said.

While evidence of several henges has been found in the area, archaeologists still know little about them.

Stephen Davis, an archaeology professor at University College Dublin, said there had not been a significant excavation since the 1970s, leaving researchers unable to precisely date the henges. If they looked below the ground, they would likely find charcoal, stone tools and bone, he said — but it is unlikely the newly identified site would be dug up since it is on private property.

MacDonagh said the National Monuments Service would continue to research the site, in consultation with the landowner, who has not been publicly identified.

Murphy, who lives about 10 minutes from the site, said he was amazed that an area that had long been under intense scrutiny could still hold such a secret.

“I’ve been studying the landscape for 20 years and I never thought I’d make a discovery,” he said. “I thought the archaeologists had discovered everything there was to be revealed.”