Rome: Forgotten Basilicas & San Clemente Underground Tour｜Italy

Most tours built around San Clemente end exactly where they begin: a ticket, a descent, an exit. Ours begins somewhere else — at Santa Maria Maggiore, one of Rome's four papal basilicas, whose walls and ceiling sparkle with centuries of frescoes and gilded coffins, a monument that most visitors rush past on their way to the Colosseum without ever entering.

From there, the journey moves to roads that not many ever reach. At Santa Prassede, 9th-century Byzantine mosaics still burn gold above an altar that almost no tourist ever sees, and in one side chapel a single column of ancient marble is said to be the very one to which Christ was bound before his flagellation. A few steps away, beneath the modest church of San Martino ai Monti, a free and almost unknown crypt preserves the foundations of a domus ecclesiae — one of the earliest known homes where the first Christians of Rome met in secret, long before churches as we know them today existed, and a rare place where you can find yourself exactly where they once were. You can go down a good 2 floors below ground level and, here, there will also be a little gem for you.


Only after this slow construction do we reach San Clemente, strolling through the beautiful Oppian Hill which provides us with a hidden and unique glimpse of the beloved Colosseum. The basilica not as an isolated stop, but as the destination to which the entire journey was built: here, history is not hanging on a wall, but under your feet, in three layers stacked one on top of the other. First, the 12th-century basilica above ground, glittering with mosaics. Then a descent into a 4th-century church, whose walls still bear intact faded medieval frescoes, which remained intact for eight hundred years. And finally, an even deeper level, a temple built for the forbidden cult of Mithras — sealed and forgotten for nearly two thousand years, its underground waterway still audible in the dark, flowing exactly where it has been since before the fall of the empire.

A licensed guide walks you through all of it, building the story stop by stop until the final descent becomes the emotional peak of the experience, not just its ticketed conclusion — a walk backward through two thousand years of Roman history, on a route no other tour in Rome recreates.
Please note that there are some stairs during the tour.