The Keyhole of the Knights of Malta is located at Piazza dei Cavalieri di Malta next to the Sant’Anselmo all’Aventino church on top of Aventine Hill. You’ll easily find this tourist attraction because you’ll witness a number of visitors queuing infront of the tall wooden door. When you peek through the keyhole, you will see a framed view of dome of St. Peter’s Basilica.
That’s the hand of my friend, she’s peeking on the keyhole.
From @tombramycin