Church of San Silvetro in Capite - Rome, Italy. The church is currently not in very good condition, but is still being used for Sunday Services.
The Basilica of Saint Sylvester the First is a Roman Catholic basilica and church dedicated to Pope Saint Sylvester. It was built in the 8th century as a shrine for the relics of the saints and martyrs from the Catacombs. The basilica is famous for a relic, a fragment of a head purported to be that of Saint John the Baptist, kept in a chapel to the left of the entrance. Strongly recommended to visit.