Basilica di San Paolo fuori le Mura

Lonely Planet review

The biggest church in Rome after St Peter's - which makes it the third-largest in the world - St Paul's Outside the Walls stands on the site where St Paul was buried after being decapitated in AD 67. Built by Constantine in the 4th century, it was largely destroyed by fire in 1823 and much of what you see today is a 19th-century reconstruction.

Among the treasures that survived the fire was the 5th-century triumphal arch, with its heavily restored mosaics of Christ with angels, Sts Peter and Paul and symbols of the Evangelists. On the other side of the arch are mosaics by Pietro Cavallini.

The gothic marble tabernacle over the high altar was designed in about 1285 by Arnolfo di Cambio together with another artist, possibly Pietro Cavallini.

Looking upwards, the papal portraits beneath the nave windows. Every pope since St Peter is represented and legend has it that when there is no space left for the next portrait, the world will fall. There are currently eight places left.

The stunning Cosmati mosaic work in the cloisters of the adjacent Benedictine abbey also survived the fire. The octagonal and spiral columns supporting the elaborate arcade are arranged in pairs and inlaid with beautiful colourful mosaics.