Knights of Malta Keyhole

Peering through the keyhole of this gate on the grounds of the Knights of Malta priory reveals an optical trick landscaped deliberately: a tree-lined avenue perfectly aligned so that St. Peter's dome appears framed in the distance, seemingly much closer than it actually is. It's a tiny, easily missed detail on a quiet residential street atop the Aventine, one of Rome's least touristy hills, which makes the payoff feel more like a discovery than a monument visit. There's often a short line of people waiting their turn to look through, but the stop itself takes only a minute or two. Combine it with the nearby Orange Garden for one of the best quiet corners in central Rome.