Buried 20m beneath the Alla Giudecca hotel in Ortygia's old Jewish ghetto (known as the Giudecca) is an extraordinary ancient Jewish miqwe (ritual bath), reputedly Europe's oldest. The baths were once connected to a synagogue, but were blocked by members of the Jewish community when they were expelled from the island in 1492. Tours, which depart every 30 minutes, are offered in English and Italian.
It's a fascinating sight – the three deep pools intended for total immersion constantly bubble with fresh water, now pumped out of the chamber to prevent flooding. To the sides of the main pools are two separate, private pools, reserved for the sole use of the rabbis.