The Venetian lagoon is a stretch of water 55km long comprised between two rivers flowing from the mainland; centuries ago, the Venetian Republic artificially moved the river-mouths so as to avoid that the detritus brought in could irreversibly inter the lagoon waters.
Always changing, this environment is a constant grabbing game between land and water; the average depth of the water is 1 meter, which is why you will often see stretches of land one day and not the next; even if not associated with Venice, the great variety of animal and plant life is rather stunning. One troublesome phenomenon is that of acqua alta – high water – which floods Venice during winter-time because of the sea tides movements.
