There are lots of things you can't do in Rome.
You can't leave your belongings unattended without fear of having them ripped off. You can't talk in the Sistine Chapel. You can't exit the Colosseum the same way you entered. You can't buy a ticket aboard a bus from a vending machine that's out-of-order. And you can't take pictures in St. Peter's Basilica.
Don't get me wrong. You can try
to take pictures of the towering marble columns, the gilded arches, and the dazzling mosaics, monuments, and altars. The Vatican encourages all kinds of photography. But the thing is, everything is so big inside the basilica,...