During part of a driving tour of ancient Rome this year, our (my wife's and my) tour guide drove us to a small courtyard on one of the hills near the Colosseum. As he parked the car, I noticed two rather serious looking militia with automatic weapons standing in the courtyard—and I hoped they weren't there for me! They had their fingers over the triggers the whole time I was there, though they seemed friendly enough as we passed by on our way to a mysterious door.
The tour guide told us that there was a delightful treat waiting for us; he told us to look into a small keyhole, not a half inch in diameter, and see what we could see. It was obvious many people had touched the door around the keyhole, so it had to be a somewhat popular thing to do.
My own suspicions made me hesitate from putting my eye to the hole—whenever I'm told to do something touristy, like rub the belly of a bronze Billiken statue, I remember what college kids did to such statues—but when my eye came into focus, I saw a brilliant and beautiful sight. A sight that cannot be adequately captured by a camera: