St. Isaac's Cathedral

Interesting facts

1. 1

   The cathedral's dome is gilded with approximately 100 kilograms of gold applied using a mercury-amalgam fire-gilding technique.

2. 2

   During World War II, the dome was painted gray to camouflage it from enemy aircraft, preventing it from being used as a target for artillery.

3. 3

   The foundation consists of over 24,000 wooden piles driven into the marshy soil to support the massive structure.

4. 4

   The cathedral is home to one of the world's largest collections of mosaic art, covering over 6,000 square meters of wall surface.

5. 5

   The pendulum of a Foucault experiment was installed under the dome in 1931 to demonstrate the Earth's rotation when the building served as the Museum of the History of Religion and Atheism.

6. 6

   The bronze doors are embellished with high-relief sculptures inspired by Ghiberti’s 'Gates of Paradise' in Florence.

Overview

St. Isaac's Cathedral is the largest Russian Orthodox cathedral in Saint Petersburg, featuring a massive gold-plated dome that dominates the city skyline. Designed by Auguste de Montferrand, the structure is a primary example of Neoclassical architecture with Russian Byzantine influences. The exterior is adorned with 112 monolithic granite columns, each weighing approximately 114 tons. The interior showcases extensive use of malachite, lapis lazuli, and gilded bronze alongside vast mosaic panels. Construction spanned 40 years, from 1818 to 1858, involving over 400,000 workers. The cathedral currently functions as both a state museum and a site for occasional religious services. The colonnade offers a 360-degree panoramic view of the historic city center from a height of 43 meters. It remains one of the tallest domed structures in the world.

Insider tips

• Climb the colonnade stairs for the best architectural perspective of the city layout.

• Bring a scarf or head covering to comply with traditional church interior etiquette if services are underway.

• Look for the 'red line' on the floor, which marks the original placement of the Foucault pendulum.