Established by decree of Doge Leonardo Loredan on March 29, 1516, the Venice's Ghetto was one of the first places where people were forcibly segregated and surveilled because of religious difference. The term itself originated here; the area had been used as a foundry (“geto” in Venice dialect) and over time the neighborhood’s polyglot residents corrupted the word to ghetto.
Though you can still see the recesses in the walls where the hinges of the portals once hung, the Venice ghetto stopped being a prison since Napoleon seized the city and tore down the gates in 1797.