“In Panini’s day, as in our own, the Pantheon was one of the great tourist attractions of Rome. Built under Hadrian in the 2nd century, this monumental domed temple has survived intact, owing to its consecration as a Christian church—Santa Maria Rotunda—in AD 609. Panini’s depiction is populated with foreign visitors and a lively mix of Romans from all social strata who congregate in the Pantheon to pray, to chat, and to admire the wondrous architecture.
Trained in architecture and theatrical design, Panini manipulated the perspective to show a larger view of the interior than is actually possible from any single place. The viewpoint is deep within the building, facing the entrance. The portals open to the colossal columns of the porch and a glimpse of the obelisk in the piazza before the church. Through the oculus in the center of the dome, Panini revealed the bright blue sky flecked with clouds.” (https://www.nga.gov/collection/art-object-page.165.html)