Peter and Paul Fortress, St. Petersburg, Russia

Dating back to 1703, Peter and Paul Fortress is the historic heart of St. Petersburg and the site of its first cathedral. The large defensive fortress was founded on Zayachy (Hare) Island in front of Troitskiy bridge to protect the lands of the Neva from possible attack by Swedish troops. From around 1720, the fort served as a base for the city garrison and also as a prison for high-ranking or political prisoners.

The fortress contains several notable buildings clustered around the Peter and Paul Cathedral, the first stone church in St. Petersburg, which was built between 1712 and 1733. The cathedral has a 122.5 m (402 ft) bell-tower, the tallest in the city center, and a gilded angel-topped cupola. Both the fortress and the cathedral were originally built under Peter the Great and designed by Domenico Trezzini.

The cathedral's architecture features a unique iconostasis, the screen which separates the nave of the church from the sanctuary. In the Eastern Orthodox Church the iconostasis is normally a flat wall or screen with three doors through it, the central Holy Doors used only for very solemn entrances, and the two side doors, by which the clergy and others enter and leave the sanctuary. However, at St. Peter and Paul, the iconostasis rises to form a sort of tower over the sanctuary. The cathedral also houses the remains of almost all the Russian Tsars (Emperors and Empresses) from Peter I to Alexander III, with the exception of Peter II and Ivan VI.

The newer Grand Ducal Mausoleum, built in the Neo-Baroque style under Leon Benois's supervision in 1896-1908, is connected to the cathedral by a corridor. Other structures inside the fortress include the still functioning mint building, constructed to Antonio Porta's designs under Emperor Paul, the Trubetskoy Bastion with its grim prison cells, and the city museum.

According to a centuries-old tradition, a cannon is fired each noon from the Naryshkin Bastion. Annual celebrations of the city day (May 27) are normally centered on the island where the city was born. The fortress walls overlook sandy beaches that have become among the most popular in St. Petersburg. In summer, the beach is often overcrowded, especially when a major sand festival takes place on the shore.