Castel Sant'Angelo

This building has had more career changes than any structure in Rome. It started as a mausoleum for Emperor Hadrian in 139 AD — the same Hadrian who built the Pantheon and the wall in Britain. It became a military fortress when the Aurelian Walls incorporated it in 401 AD. Then it became a papal castle, a prison, a treasury, and finally a museum. Its current name comes from a legend that the Archangel Michael appeared atop it in 590 AD, sheathing his sword to signal the end of a devastating plague. The bronze angel on top commemorates that vision.

A secret elevated passageway — the Passetto di Borgo — connects the castle directly to the Vatican, about eight hundred metres away. It was built as a papal escape route, and it has been used exactly as intended. In 1527, when the army of Holy Roman Emperor Charles V sacked Rome, Pope Clement VII sprinted down the Passetto in his white robes while Swiss Guards died buying him time. One hundred and forty-seven of the one hundred and eighty-nine Swiss Guards were killed in the rearguard action. Clement survived, holed up in the castle for months, and eventually surrendered.

The prison cells here held some notable inmates. Benvenuto Cellini, the Renaissance goldsmith and sculptor, was imprisoned here and later wrote about a spectacular escape in his autobiography — scaling the walls with knotted bedsheets, breaking his leg in the fall, and being recaptured. Beatrice Cenci was held here before her execution in 1599 for the murder of her abusive father — her case became one of the most famous legal dramas of the Renaissance, inspiring Shelley to write a play about her.

The top terrace has one of the best three-hundred-and-sixty-degree views in Rome. You can see St Peter's dome directly ahead, the river below, and the entire historic centre spread out behind you. There is a cafe up there. Ordering an espresso on the roof of a building where emperors were entombed and popes hid from invaders is a very Roman experience.