Below the Palazzo Ducale, the cells of the former state prison have been excavated and opened as part of the palace complex. Prisoners were held here from the medieval period until the 19th century; the walls of some cells are covered with carvings, prayers, and drawings scratched by inmates over the centuries. The experience of descending from the grand governmental spaces above into the cramped cells below gives a visceral sense of how power operated in the Republic of Genoa.
Access is through the Palazzo Ducale ticket or as a separate visit. The cells are atmospheric rather than horrifying — the carvings in particular repay slow attention.