Completed around 125 CE, the Pantheon stands as one of the most technically advanced buildings of ancient Rome and the best-preserved large concrete structure of antiquity. Its unreinforced concrete dome—still the largest of its kind—culminates in a 9-meter-wide oculus that functions simultaneously as the building’s primary light source and an environmental regulator. Rain enters freely through the opening, but the interior geometry anticipates this condition: the marble floor is subtly cambered