Aventine Keyhole

Hidden in plain sight on the Aventine Hill, this famous keyhole in the gate of the Order of Malta's priory offers one of Rome's most surprising optical illusions. Peer through the bronze keyhole and you'll see a perfectly framed view of St. Peter's Basilica at the end of a long garden corridor — the trees on either side have been carefully trimmed for centuries to maintain this exact composition.

The queue is usually short in the early morning or late afternoon. There are no tickets, no entrance fees, and no fuss — just a small moment of magic on a quiet hilltop away from the tourist crowds of the Colosseum and Forum. The surrounding neighborhood of Aventino is itself worth exploring, with orange gardens offering panoramic views over the Tiber.