Torcello 

Still habited in roman times, Torcello lived its best period with 50.000 citizens. Today Torcello count seven people: the parson, the guardian of the museum and two families.
Torcello was the first city centre which grown in the lagoon. It was one of the most ancient and prosperous centre of the lagoon, full of churches, monasteries and an effervescent economic centre till the birth of Venice.
The slow decline of Torcello starts in the XV century when starts the landfill of the rivers that flowed in the lagoon causing the "malaria".

So the island starts to depopulate and during the napoleonic period were closed the last monasteries and demolished the churches.
Nowadays in Torcello people can see only the complex formed by the Cathedral, the church of Santa Fosca and the palaces of the council and the archive.