St. Peter and Paul Fortress

St. Peter and Paul Fortress is built on Hare Island, which is what attracted Peter the Great to this area in the first place. on May 16, 1703, the first foundation stone of the fortress, was laid by Peter the Great himself. It took until 1725 to complete, with 39-foot-thick walls and 300 guns. Ironically, its first prisoner was Peter's own son, Alexei, suspected of plotting against the Tsar. Peter oversaw his son's torture and had Alexei buried under the staircase of the Cathedral, which was built between 1712 and 1732 in the Dutch style by the architect Trezzini: