Rome - On the right bank of the river Tiber in Rome stands Castel Sant'Angelo, an ominous and apparently inaccessible castle that was once a refuge of popes.
"It is one of our top attractions and no one should miss a visit," says art student Beatrice Bulzoni, who gives private, guided tours of the castle.
The Roman emperor, Hadrian, who ruled from 117 to 138, built the castle as his own mausoleum.
"A total of seven emperors were laid to rest here," tour guide Toni tells a group of visitors.