Use the where necessary.
1)... Baltic Sea
2)... Neva River
3)... Dvortsovaya Square
4)... Peter ... Great
5)... Winter Palace
6)... Summer Garden
7)... Nevsky Prospect
8)... Russian Museum

) The Baltic Sea 2) The Neva River 3) Dvortsovaya Square 4) Peter the Great 5) The Winter Palace 6) The Summer Garden 7)  Nevsky Prospect 8)The Russian Museum