Why does Venice have canals?

The City of Venice Italy was build on many small islands in the Arciatic Sea.  The canals that separate the islands are the streets of the city.  Perhaps there is no other city like Venice.  In Venice that streets are canals filled with water. 

City of Venice

Venice is an old and beautiful Italian city built on the sea.  The city stands on a cluster of small islands.  In between the islands are strips of the sea, and these are the famous canals of Venice. 

The biggest canal, called the Grand Canal, winds through the center of the city.  The buildings which line the canals are built on piles, or posts, sunk deep in the mud. 

Motor launches and graceful Venetian boats called gondolas carry people along the many canals.  When not in use, the boats are moored to posts that resemble big peppermint sticks.

At one time, Venice was a rich trading port.  Now, much trade goes to other ports.   But Venice is still famous as a historic center of art and architecture, and for its canals and gondolas.  – Dick Rogers