Hidden behind the busy storefronts of Via del Corso, the Doria Pamphilj Gallery is one of Rome’s most extraordinary and underrated museums. Housed inside the vast Palazzo Doria Pamphilj, the gallery is still owned by the aristocratic family that assembled the collection over centuries, giving the space the atmosphere of a private palace rather than a traditional museum.

Pantheon extraordinary is its immense dome, which was the largest in the world for more than 1,300 years. Even today, architects and engineers admire its perfect proportions and ingenious Roman construction techniques. At the center of the dome is the oculus, a circular opening that allows sunlight to pour dramatically into the interior. When it rains, water falls directly through the oculus and drains away through small holes in the marble floor