For all its beauty, the city of Venice was established for the most practical of reasons.
When barbarians began attacking the Roman cities of northeast Italy early in the fifth century, refugees began eyeing the islands of the Venice Lagoon as a possible sanctuary. The Roman people knew these fierce warriors were not sailors, and wouldn't know how to navigate the Lagoon's hidden shoals and channels. Attila the Hun's sack of the nearby city of Aquileia in 452 was the last straw. After that, the Romans began building their city on the water.
At first, wooden shelters were built right on the sandy surface of the lagoon's 118 islands. But as these were replaced with brick and stone structures, a firmer foundation was required. Wood pilings were driven 20 to 25 feet down into the clay beneath the sand, and limestone foundations were laid on top of the pilings.
Today, the visitor to Venice can get a sense of how the Venice Lagoon protected the city by taking an elevator to the top of the campanile, the 325-foot-tall bell tower of St. Mark's Basilica. The lagoon is shallow enough that, when the tide is low, the channels appear as a dark blue maze threading through it.
The campanile was not always open to visitors, however. Centuries after the barbarians were no longer a threat, Venetians continued to worry about invasions from across the lagoon. As a result, they allowed no foreigner to climb to the top of St. Mark's. The view would have offered a spy the solution to the puzzle of how to invade the city. The citizens of Venice, after the effort they had expended to build a magnificent city on the water, couldn't take that chance.
