You might want to spend some time browsing the exhibits at Rumyantsev Mansion, C-189 Submarine Museum, or Erarta Museum and Galleries of Contemporary Art. Yusupov Palace, St. Isaac's Cathedral, and St. Petersburg Academy of Fine Arts are notable landmarks to explore if you're in the area. You can check out the local talent at Mariinsky Theatre, Tovstonogov Bolshoi Drama Theater, and Mikhailovsky Theatre.