St. Isaac’s Cathedral in St. Petersburg was constructed to be the city’s main church and the largest cathedral in Russia. When construction began in 1819 to replace an earlier structure, it took nearly 40 years to complete. During which time three other churches had been erected in the same area. The history of the church has been troubled with stories of ghosts and wartime, but today it serves as a museum. For tourists willing to climb to the top of the dome, they will be treated to a spectacular view of the city.