The Cathedral is located on Sofia’s Square and also known as the Ascension Cathedral. The cathedral was built in 1782-1788 by the project of C. Cameron and I. E. Starov. Cathedral is the one of the first constructions in the style of Russian Classicism in St. Petersburg. The belfry was built according to the project of L.N. Benois.
Photos of the cathedral interior you can see on this link: Decor of the St. Sophia Cathedral in Pushkin.
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