Aventine Hill — the Orange Garden and the keyhole

The Aventine is the calm version of Rome: residential, leafy, and high enough that the Giardino degli Aranci — a small walled garden of orange trees — ends in a terrace with the whole city below, St Peter's dome closing the view. The central avenue of the garden, with trees on both sides and the terrace as the vanishing point, is a ready-made frame for a couple walking towards the light.

Two minutes away, at the gate of the Priory of the Knights of Malta on Piazza dei Cavalieri di Malta, is the keyhole: look through it and St Peter's dome sits perfectly centred at the end of a garden avenue. It is a real photograph, not just a curiosity — shot through the hole with a wide aperture, the keyhole itself becomes a dark frame around the dome.

Go late afternoon: the terrace faces west, so the low sun lands on faces and the city behind goes hazy and golden. Expect a short queue at the keyhole at any civilised hour — it moves fast, but each person only gets a few seconds, so have the camera settings ready before it is your turn.