The catacombs of St. Domitilla comprise one of two extensive networks of catacombs in Rome. These catacombs, dug during the first half of the fourth century, spread over 15 kilometers and are laid out on two levels, one on top the other, with a third level in two distinct areas. The catacombs are situated near a basilica that was built in tribute to Roman Christian martyrs, Nereus and Achillius. A visit to the catacombs begins in the basilica, which features sarcophagi in the floor and an altar that is believed to sit directly over the martyrs' actual tombs. The catacombs themselves can be accessed through vestibules with facades made out of yellow brick. The vestibules lead into galleries containing inscriptions and frescoes decorated with symbolic images of the soul rising into salvation. The most common tombs, called loculi, are situated along the walls of quadrangular-shaped chambers. Some tombs are blocked off by marble slabs, while others lay open without their original decoration. Lit by dim lighting, these catacombs share a slice of real history. Buses and tours are available during the day, and several hotel and dining accommodations are within a mile of the site for comfort and convenience. This is an exciting must-see while visiting the Eternal City.