Saint Petersburg Mosque is one of the city's most striking religious buildings, with a blue tiled dome and portals inspired by Central Asian Islamic architecture. It opened in 1913 and stands on the Petrograd Side, a short walk from the Peter and Paul Fortress area.
The interior is usually limited to worshippers, though occasional guided visits may be possible. Even from outside, the scale, tilework, and unusual setting make it a worthwhile architectural stop.