Castel Sant'Angelo Rome
Reached by one of the world's most beautiful bridges -Bernini's angel-clad Pont Sant' Angelo - Castel Sant'Angelo is a circular building originally constructed as the mausoleum of Emperor Hadrian that makes the perfect stop en route to the Vatican. It was converted into a papal fortress in the 6th century, and for nearly 1000 years was the key to Rome's military strength. Connected to the Vatican by underground tunnels, the castle also served as a refuge for various popes, and much of the history of building is "colorful" - if not dark.

It is Rome's chief citadel and dungeon. Be sure to get the audio guide which will help you understand the history and significance of each room. Today the building houses artwork, armor, weapons and household items of the renaissance period. Views of the Tiber and the city of Rome are picturesque from the castle, and the entire area allows for some relatively peaceful contemplation.