The Basilica of Saint Paul Outside the Walls (Basilica di San Paolo fuori le Mura) is one of the four major basilicas in Rome and is located outside the Aurelian Walls. The basilica was founded by Emperor Constantine in the 4th century over the burial site of Saint Paul the Apostle. It has undergone numerous renovations and restorations over the centuries due to various damages, including a major fire in the 19th century that destroyed much of the structure.

The current basilica was rebuilt in the early 20th century and is one of the largest churches in the world. It features a grand portico with five arches and a large bronze door, and a stunning interior with intricate mosaics and frescoes. The nave is lined with 80 columns of different types of marble, and the ceiling is decorated with scenes from the life of Saint Paul. The tomb of Saint Paul is located beneath the main altar, and there are also numerous other chapels and tombs throughout the basilica.

The Basilica of Saint Paul Outside the Walls is also the headquarters of the Order of Saint Benedict and is known for its strong ties to the Benedictine tradition. The basilica is a popular pilgrimage site for Catholics and visitors to Rome alike, and it is also a UNESCO World Heritage Site.