The Casa Bianca Mikvah is an underground Jewish ritual bath in Siracusa, thought to date from around the 6th century or earlier. It sits about 20 metres below street level, a reminder of the deep Jewish history of Sicily before the expulsions of the late 15th century.
The appeal is partly the age and partly the setting: descending below Ortigia's stone streets gives the visit a very different feel from the city's Greek and Baroque sights.