Britain’s longest standing home isn’t a clay hut or stone shack—it’s prehistoric Kents Cavern, on the English Riviera. Under the Powe family’s ownership for the past 120 years, the two-acre site has become a popular attraction open seven days a week, rain or shine, to the area’s 4 million annual tourists. And now for $3.1 million, the cave system can be one lucky buyer’s next home business, too.

Kents Cavern is a legally designated monument situated within the greater UNESCO Global Geopark. Britain’s earliest Stone Age people arrived at this winding subterranean complex 500,000 years ago. Neanderthals took up residence 400,000 years later. A jawbone fragment unearthed here still marks the oldest human remains found in northwestern Europe—and in 1924, Kents Cavern also inspired Agatha Christie’s novel “The Man in the Brown Suit.” Contemporary programming held beneath the stalactites today includes movie screenings, yoga, and even weddings.

Gilly Woodland and Alan Duckworth get married in what is believed to be the first wedding at Kents Cavern on October 4, 2008. Photo: Matt Cardy/Getty Images.

The current owner is the great grandson of Francis Powe, according to The Guardian, who bought the complex from Lord Haldon and used its land to sell kindling and stone, only giving subterranean tours on the side. Tourism became the land’s larger purpose when William Pengelly began unearthing prehistoric body parts there in the late 1800s.

After 23 years in charge, the current owner wants to retire. None of his kin are ready to take the helm, so the Powe family is relinquishing the full site for sale with Bettesworths, including not only the caves, but an acre of wooded trails populated by lifelike replicas of Ice Age animals, and a three-bedroom cottage.

An historical exhibition in Kents Cavern. Courtesy of Bettesworth

In total, the Powes have invested $1.2 million into the site by building a metered parking lot for 50 cars, a gift shop, offices, galleries, and a 100-person restaurant as well. They’ve got licenses to sell food and booze, and existing relationships with vendors around town that they’re willing to share.

“We went to the market on May 11,” Matthew Bettesworth told Artnet News, noting it’s difficult to estimate how long this site could stay up for grabs. “We have generated some significant interest already so we are hoping to agree a sale within a reasonably short timescale.”

Bettesworth says the Powe family hopes for a motivated buyer “to continue the legacy of the caves, but also to grow the business.”