St. Petersburg is named for Peter the Great, a Czar of Russia who moved from Moscow to begin this port city on the Baltic Sea. He is buried in the tomb above, with his wife, Catherine.
This fortress was begun in the early 1700s when Peter the Great was just establishing the town.
The St. Peter and St. Paul Cathedral is mostly used now as a museum.
http://en.wikipedia.org/wiki/Peter_and_Paul_Cathedral 
