St. Isaac's Cathedral is one of the most majestic and monumental structures of St. Petersburg, the city’s largest Orthodox Church. 43 minerals were used for the decoration of its exterior facades. Its striking interior decorations feature all kinds of monumental and decorative arts, from paintings and sculptures, to mosaics and colored stone used as finishing details. The city’s best architects, painters and sculptors worked at the construction and decoration of St. Isaac's Cathedral for 40 years.

The cathedral was consecrated in honor of St. Isaac of Dalmatia, who was much revered in St. Petersburg, and not by chance — Peter I’s birthday (May 30) coincided with St. Isaac's Day. The first St. Isaac's Cathedral was built on the Neva River embankment in the first years of the city’s existence: in that wooden church Emperor Peter the Great and Empress Catherine I were married. Over the time the church was rebuilt twice. However, in the beginning of the XIX century tsar Alexander I decided the church was too small and did not match the splendor of the capital. In 1818 a contest was announced for the best reconstruction plan. The contest was won by a young French architect August Montferrand. He was appointed the chief architect, and headed the reconstruction works which lasted for 40 years and resulted in the construction of St. Isaac's Cathedral in its present form. The golden dome of the cathedral is surrounded by an observation platform, which offers a magnificent panoramic view of the city.