What feature does the Pantheon’s rotunda specifically highlight?

The feature that the Pantheon’s rotunda highlights is the hemispherical dome, which is one of the most significant aspects of its architectural innovation. The dome is constructed using a series of concrete segments, gradually decreasing in thickness toward the top, and is one of the largest unreinforced concrete domes in the world. Its oculus at the center allows natural light to illuminate the interior, creating a dynamic interaction between light and space. This design not only showcases the technical prowess of Roman engineering but also enhances the sense of grandeur and celestial connection that the Pantheon embodies as a temple dedicated to the gods. The harmonious proportions of the rotunda and dome demonstrate the Romans' understanding of geometry and scale, making this architectural feature a defining characteristic of the Pantheon.