A hidden gem: the Protestant Cemetery, Rome. It is beautiful, as you can see. The poets Keats and Shelley are buried here, there are beautiful sculptures on some of the tombs, the ancient Pyramid of Cestius.
Pantheon, Rome - commissioned by Marcus Agrippa during reign of Augustus 27 CE; rebuilt by Hadrian Classic Romanized Greek portico introduces, but also disguises, cylindro-spherical interior. Dedicated to deities of the known planets, buil