Castel Sant'Angelo, also known as the Mausoleum of Hadrian, is a historic fortress located along the banks of the Tiber River in Rome, Italy. Originally constructed as a mausoleum for Emperor Hadrian, it has served various roles throughout history, including a papal residence and a military fortress. Today, visitors can explore its rich history through the museum housed within, which features a fascinating collection of artifacts and art. The terrace offers breathtaking panoramic views of Rome, while the spiral ramp provides a unique architectural experience. Additionally, the castle hosts various exhibitions and cultural events throughout the year, making it a must-visit destination for history enthusiasts and casual tourists alike.