Piombi
Venice, Italy · built 1500
Piombi ("The Leads" in English) is a former prison in the Doge's Palace in Venice. The name of the prison refers to its position in the attic, directly under the roof of the palace, which was covered with slabs of lead. In winter, these slabs let the cold pass and they acted as a conductor in the summer heat, imposing harsh conditions for inmates.
Prison data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).