St. Isaac's Cathedral, St. Petersburg, Russia. Saint Isaac's Cathedral or Isaakievskiy Sobor is the largest orthodox basilica and the fourth largest cathedral in the world. It is dedicated to Saint Isaac of Dalmatia, a patron saint of Peter the Great, who had been born on the feast day of that saint. The cathedral's main dome rises 101.5 metres and is plated with pure gold. The dome is decorated with twelve statues of angels by Josef Hermann. These angels were likely the first large sculptures produced by the then novel process of electrotyping, which was an alternative to traditional bronze casting of sculptures. Montferrand's design of the dome is based on a supporting cast iron structure. It was the third historical instance of cast iron cupola after the Leaning Tower of Nevyansk (1732) and Mainz Cathedral (1826)
