Consider walking around the south side of the walls around the Vatican, seeing the relationship of the piazza to that area... There's not much north of the Vatican except a touristy shopping district...
Takes at least half a day if not longer. But ABSOLUTELY worth it. Make sure you do a guided tour. Well worth the price. We did Maximus Tours (good price, great guide): Takes at least half a day if not longer. But ABSOLUTELY worth it. Make sure you do a guided tour. Well worth the price. We did Maximus Tours (good price, great guide): http://www.vaticantou...miprivate/7…see moresee less