This architectural wonder still stands as the world's largest unreinforced concrete dome two thousand years after being built. The opening at the dome's centre (known as an Oculus) is the singular source of light for the immense chamber.
Constructed in 126 C.E. by Marcus Agrippa as a temple to all the Ancient Roman gods, the Pantheon has since become a beacon of Christianity. The structure has been burned, rebuilt, robbed, modified, torn down and renovated so many times the interior contains a myriad of conflicting icons and symbols. Apparently, most gods had this building constructed in their honour. I, however, recommend worshipping at the modern-day espresso bars surrounding it.