The structure is described as a “unique and extremely interesting find” from Crete’s Minoan civilization, famous for its sumptuous palaces, flamboyant art and enigmatic writing system.

Resembling a huge car wheel from above, the ruins of the labyrinthine, 1,800-square-meter (19,000-square-foot) building came to light during a recent dig by archaeologists, The Independent reports.

The site was earmarked for a radar station to serve a new airport under construction near the town of Kastelli. Set to open in 2027, it’s projected to replace Greece’s second-biggest airport at Heraklion, and is designed to handle up to 18 million travelers annually.

Archaeologists don’t yet know what the hilltop structure was for. It’s still under excavation and has no known Minoan parallels. So for the time being, experts speculate it could have been used for a ritual or religious function.

Ringed by eight-stepped stone walls up to 1.7 meters (5.6 feet) high, the inner structure was split into smaller, interconnecting spaces and may have had a shallow conical roof.

The ministry’s statement said it didn’t appear to have been a dwelling, and the finds from inside it included a large quantity of animal bones.

“It may have been periodically used for possibly ritual ceremonies involving consumption of food, wine, and perhaps offerings,” the statement said.

“Its size, architectural layout and careful construction required considerable labour, specialised know-how and a robust central administration,” it said, adding it was certainly some kind of communal building that stood out in the entire area.

Culture minister Lina Mendoni, an archaeologist, pledged that the find would be preserved while a different location would be sought for the radar station.

“We all understand the value and importance of cultural heritage … as well as the growth potential” of the new airport project, she said. “It’s possible to go ahead with the airport while granting the antiquities the protection they merit.”