Bussana Vecchia, Liguria
Abandoned after an earthquake in 1878. Gradually repopulated by artists and hippies in the sixties. A stand-off with the Italian government ensued, and after a tense time when eviction (with violence) was threatened, instead the government made safe as much of the remaining buildings as possible and allowed the people to continue living and working there. Which they still are.
Can't believe I've lived here six years before visiting.
I think it is technically in Imperia, but a very cool place. We were cycling in Piemonte a few weeks back. Got down into Liguria a couple of times. Nice part of the world, for sure.