St Petersburg is known as the Venice of the North and is famous for its canals which separate the various islands it is located on. The parts of St Petersburg north and south of the Neva are connected by bridges which rise at night, so make sure you are on the island you need to be before they go up, otherwise you might be stuck there for a couple of hours. Timetables can be found on bridges denoting the hours when they open and close.
The city has many sights worth seeing and not all of them are located in the very centre of the city, although a large portion of them are located around the main thoroughfare of Nevsky Prospekt which runs across the city from close to the Winter Palace on 2-y Admiralteysky Island down to Aleksandro-Nevskaya Lavra on Bezymyanny Island. Nesvky Prospekt is also a tourist experience in itself, great for strolling along and with lots of souvenir shops, cafes and restaurants. For ease we have divided St Petersburg into several sections based on its islands rather than its official districts: the central islands between the Neva and the Fontanka, the area to the north of the Neva and the area to the south of the Fontanka.