St. Petersburg is Russia's second-largest city after Moscow, and throughout history, it has been known by a few different names. In the more than 300 years since it was established, St. Petersburg has also been known as Petrograd and Leningrad, though it's also known as Sankt-Peterburg (in Russian), Petersburg, and just plain Peter.
Peter the Great founded the port city of St. Petersburg on the very western edge of Russia in 1703 in a marshy floodplain. Located on the Baltic Sea, he desired to have the new city mirror the great Western cities of Europe, where he had traveled while studying in his youth. Amsterdam was one of the primary influences on the czar, and the name St. Petersburg has a distinctly Dutch-German influence.
St. Petersburg saw its first name change in 1914 when World War I broke out. The Russians thought that the name sounded too German, and it was given a more "Russian-sounding" name "Petrograd". The Petro start of the name retains the history of honoring Peter the Great. The -grad portion is a common suffix used in a number of Russian cities and localities.
It was only 10 years that St. Petersburg was known as Petrograd because in 1917 the Russian Revolution 503 changed everything for the country, including the city's name. At the beginning of the year, the Russian monarchy was overthrown, and by year's end, the Bolsheviks had taken control. This led to the world's first communist government. Vladimir Ilyich Lenin led the Bolsheviks, and in 1922 the Soviet Union was created. After Lenin's death in 1924, Petrograd became known as Leningrad to honor the former leader.
Fast-forward through almost 70 years of the communist government to the fall of the USSR. In the years that followed, many places in the country were renamed, and Leningrad became St. Petersburg once again. Historical buildings saw renovation and rejuvenation. Changing the city name back to its original name did not come without controversy. In 1991, the citizens of Leningrad were given the opportunity to vote on the name change.
In the end, St. Petersburg was returned to its original name, but you will still find some people who refer to the city as Leningrad.