Peter and Paul Fortress

The Peter and Paul Fortress is the original citadel of St. Petersburg, Russia, founded by Peter the Great in 1703 and built to Domenico Trezzini's designs from 1706 to 1740 as a star fortress. Between the first half of the 1700s and early 1920s it served as a prison for political criminals. It has been a museum since 1924.Today it has been adapted as the central and most important part of the State Museum of Saint Petersburg History. The museum has gradually become virtually the sole owner of the fortress building, except the structure occupied by the Saint Petersburg Mint.

Source: Wikipedia