Most of the architectural designs of Roman buildings were inspired by the ancient Romans and their famous inlays in education, infrastructure and culture. This is proof in the Castle Sant’ Angelo in Rome. Constructed for the mausoleum for the Emperor Hadrian, this circular building is accessed via Benini’s Port Sant’ Angelo bridge. The now converted museum is—was—converted into a papal fortress in the 6th century and is linked to the Vatican by underground passages.