 Recognised as World Cities, they feature such world-renowned museums as the Tretyakov Gallery and the Hermitage, famous theaters like Bolshoi and Mariinsky, ornate churches like Saint Basil's Cathedral, Cathedral of Christ the Saviour, Saint Isaac's Cathedral and Church of the Savior on Blood, impressive fortifications like the Kremlin and Peter and Paul Fortress, beautiful squares and streets like Red Square, Palace Square, Tverskaya Street, Nevsky Prospect, and Arbat Street.Rich palaces and parks are found in the former imperial residences in suburbs of Moscow (Kolomenskoye, Tsaritsyno) and St Petersburg (Peterhof, Strelna, Oranienbaum, Gatchina, Pavlovsk and Tsarskoye Selo).Moscow displays Soviet architecture at its best, along with modern skyscrapers, while St Petersburg, nicknamed "Venice of the North", boasts of its classical architecture, many rivers, canals and bridges.