Castel Sant'Angelo

A massive round drum of brick and stone rises from the bank of the Tiber, topped by a bronze angel with outspread wings. A bridge lined with marble angels leads across the river toward it. This is Castel Sant'Angelo, a building that began as a tomb for an emperor and became, by turns, a fortress, a prison, and a refuge for popes.

It started as a mausoleum. The emperor Hadrian built it in the second century, around 139, as a grand circular tomb for himself and his family, faced in marble and crowned with statues. Much of that decoration is long gone, but the huge cylindrical core survives as the heart of everything built since.

Its position by the river, close to what became the Vatican, gave it a second life as a fortress. Over the centuries it was strengthened into a castle guarding the approach to the papal city, its old tomb chambers turned into ramparts, store-rooms, and gun positions.

A raised, walled corridor connects the castle to the Vatican, a private escape route for the popes. In times of danger a pope could slip from his palace to the safety of the fortress along this passage, and at least one did exactly that when the city was sacked in the sixteenth century.

The castle takes its name from a legend. The story tells that, during a deadly plague late in the sixth century, the Archangel Michael appeared above the building, sheathing his sword to signal the end of the sickness. The bronze angel on the top, replaced over the years, remembers that vision.

Inside, a spiral ramp built for the emperor's funeral leads up through the ancient core, and above it lie centuries of later rooms — papal apartments with painted ceilings, grim prison cells, armouries, and store-rooms. Climbing through, you pass from Roman tomb to Renaissance palace to fortress in a single route.

The prison cells are part of the darker story. Over the centuries the castle held many prisoners, some of them famous, in conditions ranging from comfortable confinement to harsh dungeons, and that history of captivity sits oddly alongside the richly painted rooms of the popes nearby.

The reward at the top is the terrace. From the open platform around the base of the bronze angel, you get one of the finest wide views in Rome, along the river, over the rooftops, and across to the great dome of Saint Peter's, close enough to feel you could almost touch it.

The bridge in front of the castle is a sight in its own right. Lined with marble angels designed by a great Baroque sculptor and his workshop, each carrying a symbol of the crucifixion, it is one of the most beautiful river crossings in the city, especially in low evening light.

The castle now works as a museum, its rooms holding sculpture, paintings, arms, and the layered history of the building itself. It is large enough to reward a couple of hours, moving slowly upward from the ancient base to the terrace at the summit.

A few practical notes. Entry is ticketed, and booking ahead saves queueing in summer; the climb involves ramps and stairs but is gradual rather than steep. Late afternoon rewards you with warm light on the terrace and on the dome of Saint Peter's, a fine time to make the climb.

Stand on the terrace by the angel before you go back down, with the river bending below and the city spread out around you. Few buildings have lived so many lives — tomb, fortress, prison, palace, and refuge — on a single spot. When you cross back over the angel-lined bridge, the long story of the place goes with you.