Piazza dei Cavalieri di Malta

Lonely Planet review

At the southern end of Via di Santa Sabina, this peaceful little square takes its name from the Cavalieri di Malta (Knights of Malta), who have their Roman headquarters here, in the Priorato dei Cavalieri di Malta. Although it's closed to the public, the priory offers one of Rome's most charming views: Look through the keyhole and you'll see the dome of St Peter's perfectly aligned at the end of a hedge-lined avenue.

An 18th-century masterpiece, the priory is the only architectural work of Giovanni Battista Piranesi, an artist better known for his etchings and engravings of Roman ruins.

The Knights of Malta were founded in the 12th century in Rhodes and later spread to Malta to protect pilgrims en route to the Holy Land. The villa is the residence of the grand master of the Knights of Malta and has, in the past, served as the order's embassies to Italy and the Holy See.