Pantheon Stuff

At the back of the Pantheon is the remnant of an ancient structure known as the Basilica of Neptune. It was originally attached to the Pantheon complex during Emperor Hadrian’s reconstruction in the 2nd century CE. The niche you see likely formed part of that basilica or a similar structure. The fragmentary Corinthian column, with its fluting, is part of that ancient architecture. While much of the Basilica of Neptune is gone, these remains hint at the grand complex that once surrounded the Pantheon.

The trenches around the Pantheon, especially on the left-hand side, aren’t ancient water channels. Instead, they are the result of excavations that revealed the original ground level of ancient Rome. Over time, the city’s ground level rose significantly due to centuries of debris and rebuilding. When the Pantheon was built, it stood on a lower plane. These modern trenches, essentially sunken walkways, let you see how deep the original entrance level was. They highlight how much the city’s ground level has risen since antiquity. So, in short, they’re modern excavations, not ancient water drainage.