The most notable building in the complex of Peter and Paul’s Fortress is the Peter and Paul Cathedral. Its golden spire became the symbol of Russian’s security on the Neva banks and at the same time the symbol of the modern city. The cathedral was founded in 1712 and construction works were finished only in 1731. Designed to the project of D. Trezini, the architect great number of outstanding buildings in St.Petersburg, Peter and Paul Cathedral built in early baroque style is his unexcelled masterpiece. The rectangular building is dominated by a tall bell-tower which is designed in tiers. It is crowned with a weather vane in the shape of angel holding a cross. The angel look tiny from below, but in fact, it is 3,2 meters high with a wing span of  3,8 meters.

The interior of the cathedral differs much from traditional Russian churches and bears a strong resemblance to the interior of a gala room of the 18^th century. There is a marble imitation on the walls and pillars which uphold the vault while churches are usually decorated with frescos. Painting of the walls and pillars, beautiful moldings, gilt and ornament painting of the vaults performed by talented masters such as Negrubov and Vorobyov provide an impression of luxury and triumph. During the WWII the Peter and Paul cathedral was not damaged terrible, so after the restoration works of 1950s the visitor can justice the iconostasis created by talented Moscow architect-Ivan Zarudny as a three-spanned twenty meters high triumphal arch - a unique example of Russian folk craftsmanship. 43 icons of the iconostasis were painted by a group of Moscow  artist. Famous not only for its outstanding decorations, but also as a burial place of the Romanovs, Peter and Paul’s Cathedral became the royal sepulcher for all the tsars starting with Peter the Great daughter up to Alexander III (except Peter II who died in Moscow and was buried there).