What does the "oculus" in the Pantheon do?

The oculus in the Pantheon primarily functions to allow sunlight and rain to enter the rotunda, making it a key architectural feature of the building. As the central opening at the top of the dome, the oculus creates a connection between the interior space and the outside environment. This not only illuminates the interior with natural light, creating a dynamic effect as the light shifts throughout the day, but it also serves as a symbolic link to the heavens.

The design of the Pantheon, with its massive dome and oculus, also emphasizes the grandeur and majesty of the space, elevating the experience of those within. The incorporation of natural elements, such as sunlight and weather, enriches the overall sensory experience of the rotunda.

While the oculus does play a role in the structural integrity of the dome by alleviating some weight and pressure at the center, its primary purpose is related to light and atmosphere rather than load-bearing functions. Therefore, while it fulfills various roles within the architecture, its most significant contribution is facilitating this relationship between the interior of the Pantheon and the external environment.