The Peter and Paul fortress was built on the orders of Peter the Great between 1706 and 1740 and is a star fortress located on Zayachy (Hare) Island in the Neva River. It was used as a garrison and as a prison before being converted to a museum in 1924. Today visitors can visit the Peter and Paul Cathedral, plus museums dedicated to space exploration, science and technology, and the history of St. Petersburg.