Originally built in AD 135 as a mausoleum for Emperor Hadrian, Castel Sant'Angelo has a fascinating history spanning multiple centuries. Over time, the structure transitioned from being Hadrian’s final resting place to a military fortress during the Middle Ages, and later became the property of the Papal States. This evolution has imbued the building with unique layers of historical significance, which can be appreciated in its different architectural elements and art collections.

Today, Castel Sant'Angelo is a museum where visitors can explore the various rooms used as papal residences, fortifications, and even dungeons. From the renowned 'Terrazzo dell'Angelo' (the Angel's Terrace), visitors are treated to one of the most stunning panoramic views of Rome, including sights of the Vatican and across the Tiber River.

The castle also serves as a place of cultural heritage, housing sculptures, frescoes, marble artifacts, weapons, and memorabilia that illustrate Rome's diverse history. The Passetto di Borgo, a passage connecting the Vatican to the castle, played a crucial role in providing an escape route for Popes during times of crisis, such as the notorious Sack of Rome in 1527.

Visitors are drawn not only by its history but also by its enigmatic atmosphere that is filled with stories of intrigue, political turmoil, and artistic masterpieces. Notable highlights include the papal apartments with impressive Renaissance frescoes and a small restaurant with a breathtaking view, which makes the visit even more delightful.