The Keyhole on Aventine Hill: A Hidden Gem Worth Finding
This buco della serratura allows you to see three countries at once: the Order of Malta, Italy, and Vatican City. The Villa represents the Order of Malta, home of the Knights, while the rest of Rome seen through the keyhole is Italy.
And the dome of St. Peter’s Basilica belongs to the independent State of Vatican City. Adding to the curiosity is the fact that the Order of Malta is the only state without a territory in the world.
The keyhole acts like a camera obscura, creating a projected image of the distant basilica on the inner wall of the door. The effect is like a miniature postcard of the dome of St. Peter’s.