Uspenski Cathedral was built between 1862 and 1868. It was designed by Aleksei Gornostajev and based on a 16th-century church near Moscow. The bricks came from the Bomarsund fortress in Aland, which had been destroyed during the Crimean War in 1854.

Today, the cathedral is the seat of the Archdiocese of Helsinki in the Finnish Orthodox Church. The Finnish Orthodox Church has about 60,000 members and is part of the Ecumenical Orthodox Patriarchate based in Constantinople.

The exterior of Uspenski Cathedral is not elaborately decorated, but is nevertheless striking with its deep-red brick walls and green-and-gold onion domes.
There are 13 onion domes in all, representing Christ and the twelve apostles.

As the largest Orthodox church in western Europe, the cathedral also impresses by its sheer size. The central dome is held aloft by four monolithic granite pillars.

Inside, the cathedral houses a rich display of icons and other typical Orthodox decorations, including an impressive array of chandeliers hanging from the vaulted ceiling. One of the icons is believed to work miracles.