☦ Solovetsky Monastery - White Sea The Solovetsky Monastery is a fortified monastery located on the Solovetsky Islands in the White Sea in northern Russia. It was one of the largest Christian strongholds in northern Russia before it was converted into a Soviet prison labor camp in 1926–1939 and served as the prototype for the camps of the Gulag system. The monastery survived several major changes and military sieges. Photo: Alexey Zadonsky · CC BY-SA 4.0