Talk about canals in Italy and, of course, Venice comes to mind. But hundreds of years before its construction was even started, the city of Ravenna, to the south in what is now Emilia Romagna, was already there. Its origins are a mystery. It was probably built by the Etruscans, around 625-700BC. They were skilled hydraulic engineers, draining the marshlands and constructing a complicated network of canals, which also channelled water for farming purposes.
During Roman Times
In the 1st century BC, the Romans arrived and took over the city. Perfect mosaic floors and other remains are still being discovered 6-7 mts below street level. Strabo described Ravenna as:
'A city built entirely on wooden piles and coursed by rivers, it is provided by thoroughfares by means of bridges and ferries. Here the drift of the tide together with the river currents purify the swamps by removing their ooze and filth; hence human settlement becomes possible in a space usually populated by insects, frogs and snakes, and a flourishing economy develops, mainly based on controlling trade and inland waterways. The place is considered so healthy that it is chosen for feeding and training gladiators. Now this is one of the marvellous things at Ravenna – I mean the fact that the air in a marsh is harmless.'.
In 27BC, Augustus started work on enlarging Ravenna's port. It eventually had room for 250 ships, plus several acres of storage on the land. Augustus also built the Fossa Augusta; a deep canal which ran under Ravenna's town walls, and two miles to the sea.Via http://www.italymag.co.uk/italy-featured/ravenna/ravennas-lost-canals-and-their-history