You can climb to the top of the Dome of Saint Peter’s. You pay 4€ to take the stairs, 7€ to get halfway by elevator. We had already done a fair chare of stairs, so went for the elevator (the operators were rude). First stop is the inside of the Cupola, you get to walk halfway round, standing next to the huge mozaiks which look like paintings seen from below. After this the climb to the top begins (over 300 stairs). The winding stairs are small, steep and narrow, it gets pretty claustrofobic at times. After a lot of wheezing we got to the top, and the view is excellent. Worth the hike!