Castel Sant'Angelo

Lonely Planet review

With its chunky round keep, this castle is an instantly recognisable landmark. Begun by Emperor Hadrian in 128 AD as a mausoleum for himself and his family, it was converted into a fortress for the popes in the 6th century AD. It was named by Pope Gregory the Great in AD 590, after he saw a vision of an angel above the structure heralding the end of a plague in Rome.

Later, in 1277, it was linked to the Vatican palaces by a wall and passageway, often used by popes to escape in times of threat. During the 16th-century sack of Rome by Emperor Charles V, hundreds of people lived in the fortress for months. On the upper floors, check out the lavishly decorated Sala Paolina and the Camera del Perseo and Camera di Amore e Psiche, both with friezes by Perino del Vaga. The terrace, immortalised by Puccini in his opera Tosca, offers great views over Rome.