'Secret house' (Corps #2) or Old Jail in Schlisselburg fortress

It was built in 1798 in the courtyard of the Citadel from the stone of the dismantled upper tiers of the fortress towers. It was the former main political prison of the Russian Empire. It had 10 single cells ('rooms'). At one time, this was quite enough to maintain the state security and social harmony. In 1907, it underwent restructuring. The prison existed until 1917. Since 1928 there is a prison museum. During the 1941-44 war it was heavily damaged, then restored and reopened as a museum in 1966.