One of the most surprising places in Estonia is forty kilometres southeast of Tallinn: the former prison and the flooded quarry of Rummu. The site is actually not open to the public and is cordoned off by the owner. Nevertheless, residents of the area as well as travelers often find a way through the fence to bathe in the unusually clear water. The prison and quarry were built in the late 1930s to mine limestone. The inmates had to work there and the institution was notorious for its human rights violations. At least one prisoner died under dubious circumstances each year, and inmates tried to force hunger strikes to improve prison conditions.
When Estonia gained independence from the Soviet Union in 1991, the quarry was closed. After the pumps were turned off, the mining area quickly filled up with groundwater and flooded some of the buildings up to the second floor. So there are still lanterns, barbed wire, mining tools and an entire forest under water which now serve as an attraction for divers. The prison next to the quarry only closed in 2012.