It is connected with the mainland, 21/2 miles (4 km) away, by motor-car and railway causeways. The city's canals, crossed by as many as 400 bridges, replace the streets of ordinary towns. The principal traffic artery, the Grand Canal, curves through Venice from the modern railway station to the Piazza San Marco, a huge square, inhabited by many pigeons, to which tourists flock in large numbers to visit the ornate church of St Mark's, the clock tower, and the campanile (bell tower).
Adjoining the square is the Palace of the Doges (residence of the medieval rulers of Venice) and the Bridge of Sighs, over which prisoners used to be led to their cells. The Grand Canal is lined with sumptuous palaces, built hundreds of years ago by the city's wealthy merchants.
During the latter part of the Middle Ages, Venice was the centre of European commerce with the Orient; it successfully competed with Genoa (1380) and established strategic bases in the eastern Mediterranean, including Constantinople (Istanbul).
However, its trading monopoly was broken at the end of the 15th century, when Portuguese navigators discovered a route to India around southern Africa. The city's tourist trade is all-important. The Lido, a fashionable bathing resort on the sandbar which encloses the Lagoon of Venice, is reached by ferry-boat. Venetian glassware, blown and cast in many colours, has been the city's most famous product for many centuries.