During the first half of the 2nd century AD, one of the most important buildings in the history of Western architecture was erected in Rome: the Pantheon. Its main and most impressive feature is its coffered concrete dome, which ends in a perfectly round central opening. This oculus kicked off a series of later projects that noted the value of circular openings, which were replicated as glazed skylights and as compositional elements on facades. This eventually evolved, for example, towards the detailed and colorful rose windows of the Gothic basilicas. In all its configurations, the oculus (eye in Latin) holds a symbolism that goes beyond the traditional window: its luminous projection gracefully marks the passage of time, solemnly highlighting an architectural space.