This imposing, seaside complex in the Kalamaja district is now one of the best places in the world to catch a glimpse of Soviet-era prison life in all its dreariness. Originally opened as a sea fortress in 1840, it housed inmates from 1919 until 2004, and has been left virtually untouched since. Most of the year the prison is closed to visitors, but you can still see it from the outside. But from May through September The Estonian Institute of Historical Memory has opened an exhibition area 'Communism is Prison' which is introducing the ideology and international crimes of communism and the history of the complex. Entrance to the area is from the side facing the Port of Tallinn from Suur-Patarei street through the gate, or from the seaside promenade through the small gate.