A former prison in Estonia that is now underwater is already popular with beachgoers and underwater divers in summer, but a new drone video shows how the unusual destination is also remarkable in winter.

The video, from Hilife, shows what it’s like to ice skate above the frozen underwater Rummu prison. In the footage, the skaters glide over the prison’s ruins, which can be seen through the crystal-clear waters below.

“The water/ice was so clean that you could see everything underneath our feet,” wrote Alari Teede and Meelis Vosu on Facebook.

According to Estonia’s tourism website, the prison camp, where prisoners would mine limestone from the quarry, was opened in 1938.

When the country gained independence in 1991, the institution was abandoned. Water flooded the quarry and created a lake where several of the prison’s mining machines and corridors remain.

If you'd like to see it in person, there are lighted raft tours and diving sessions offered at the lake.