Saint Isaac's Cathedral
Built between 1818 and 1858, the Saint Isaac’s Cathedral of Saint Petersburg, the largest Orthodox church and the fourth largest cathedral in the world, is devoted to Saint Isaac of Dalmatia. The classical exterior reflects the typical Russian-Byzantine design of a Greek-cross floor plan with a wide central dome and four subsidiary domes. Its insanely luxurious interior is open as a museum, while ceremonies are held throughout the year in the cathedral. Many people skip the museum to ascend the colonnade around the drum of the dome, which offers a beautiful view of the area.