(LIVE SCIENCE) — When Mustafa Şahin first saw photographs of the submerged ancient church under the waves of Turkey’s Lake Iznik, he couldn’t quite believe what he was seeing.

The head of archaeology at Bursa Uludağ University had been searching the shores of the lake for several years, but it wasn’t until local government surveyors showed him some aerial photographs in 2014 that he realized the lake itself covered the ancient ruins he was looking for.

“When I first saw the images of the lake, I was quite surprised to see a church structure that clearly,” Şahin told Live Science in an email. “I was doing field surveys in Iznik [since 2006], and I hadn’t discovered such a magnificent structure like that.”