Built in the 9th Century, San Nicola's foundations and columns show the
three Roman temples of Janus, Juno and Spes that once stood here. A visit
to the basement shows its earliest layers. The columns of the three temples
are visible both inside and on the outer walls. A fourth temple has also
been discovered in recent times not far away. San Nicola takes its name
"in Carcere" from the prison that once stood here.