Venice spread over 118 islands and founded in the 5 century became a major maritime power in the 10th century. The whole city and its lagoon is an extraordinary architectural masterpiece in which even the smallest building contains work by some of the world’s great artists such as giorgione , titian , tintoretto , veronese etc . The most famous place in venice is piazza san marco , or st marks square the centre from which rises the homonymous , five domed st marks basilica . Bronze horses dominate its main entrance while the interior is covered in mosaics ( mostly in gold ) that recounts scenes from the bible. Next to basilica is ducal palace which has the elaborate and lavish higher council hall . The bell tower in front was constructed in 1902 . Bridges here are distinctly different such as rialto bridge and bridge of sigh . The city of venice and its lagoon which covers 50, 000 sq km were designated a unesco world heritage site in 1987 .