The Tiber Island and St. Nicholas in prison underground tour
The Tiber Island is one of the two islands in the Tiber river, which runs through Rome; the other, much larger one, is called Isola Sacra and is near the mouth of the river at Ostia. Tiber island is located on the southern bend of the Tiber and has been connected with bridges to both sides of the river since antiquity.
Being a seat of the ancient Temple of Asclepius and later a hospital, the island is associated with medicine and healing. There is a legend which says that after the fall of the hated tyrant Tarquinius Superbus (510 BC), the angry Romans threw his body into the Tiber. His body then settled onto the bottom, where dirt and silt accumulated around it and eventually formed Tiber Island.
In ancient times, before Christianity spread through Rome, Tiber Island was avoided because of the negative stories associated with it. Only the worst criminals and the contagiously ill were condemned there. This, however, changed when a temple was built on the island.
From the island, you'll reach the ancient church of San Nicola in Carcere (St. Nicholas in Prison). The church is entirely constructed on three temples of the 3rd and 2nd centuries BC. The temple of Junos Sospita, the central one, was fully incorporated into the church in the middle ages.
From the crypt under the altar, you'll descend to the underground level and arrive in the spaces at the time open to the sky-between the three temples. You'll be on the beaten path of the Romans, who for centuries passed this way on their daily comings and goings.