Video report by ITV News' Lucy Watson
These are Italians taking a stand, in the water and on land, trying to protect Venice from this:
An unstoppable 900 foot long cruiseliner smashing into a smaller tourist boat. The danger these megaships pose couldn't be more obvious and campaigners want them banned.
One protester said: "These ships are not safe. They're too big, they pollute too much. They disrupt the water and they damage our homes."
Another added: "This is not a dock, that ship could have smashed into houses. This shore is very narrow and fragile."
Big ships may mar this city's beauty but they bring in the money. Tens of thousands of daytrippers pour off them every day.
Tourism often clogs its streets and ships congest its waterways, but Venice isn't the maritime trading power it once was.
A solution must be found to protect the fragility of this floating city.