Piazza dei Cavalieri di Malta

Map
Piazza dei Cavalieri di Malta, Aventine Hill, Rome
Piazza dei Cavalieri di Malta
The Piazza dei Cavalieri di Malta, on the Aventine Hill, was designed by the Venetian print-maker Giambattista Piranesi (1720-78), who is much better known for his etchings of Rome. The piazza (1765) was commissioned by Giovanni Battista Rezzonico, the nephew of Pope Clement XIII (r. 1758-69), and Prior of the Knights of Malta.  
Piazza dei Cavalieri di Malta, Aventine Hill, Rome
East Side of Piazza dei Cavalieri di Malta
The walls on two sides of the piazza sport small obelisks and a set of curious bas-reliefs. 

Piranesi also designed the entrance to the gardens of the Priorato di Malta, on the west side of the piazza. The door boasts the most famous keyhole in Rome. ​
Bas-relief by Piranesi, Piazza dei Cavalieri di Malta, Rome
Bas-relief