Without question, the Vatican is impressive. 0.44 square kilometers (0.16 square miles) contains a substantial chunk of the world's top art, sculpture, and maps (the map galleries are amazing-- even if you're not a geography dork!), the gardens, the necropolis and Saint's Tomb, plus a few chapels-- the Sistine Chapel and St. Peter's Basilica among them!
The guided tour of the Vatican Museums is well worth it-- it would be overwhelming for normal people like us otherwise-- and the Sistine Chapel is much smaller than expected, yet gorgeous inside. It would've been even better if it wasn't for the fact that half of the tourists inside refuse to shut up. What would be a truly breathtaking, surreal experience in dead silence instead feels like a tourist trap full of babbling idiots...
St. Peter's Basilica is the opposite experience-- it seems like it could hold a dozen Sistine Chapels, a minor painting and archway inside is easily suitable for the main altar of 99.999% of other churches churches in the world, and combine them all together, it really is breathtaking. Magnificent barely beings to describe it. And it overwhelms St. Peter's Square (St. Peter's Piazza) right outisde by a fair amount!
Strictly speaking, though, St. Peter's Basilica is truly unique. By comparison, St. Peter's Square has quite a few other locations in the world that are its equal or surpass it-- except none of those others are in the Vatican. We made it to Castle of St. Angelo afterwards, but had to skip the Vatican Gardens as we couldn't get tickets. After seeing so much at The Vatican, walking down the road to Castel Sant'Angelo (Italian spelling) seems almost plain!
A second day in a row of late lunches due to our crazy schedule followed. We walked down to the Jewish ghetto for an excellent (if rather expensive) meal at Salumeria Roscioli, crossed over to Isola Tiberina, then walked back towards Trevi Fountain for gelato at San Crispino, one of the most famous places in the world for gelato. We theoretically should've made it back down to Trastevere for pizza at Ai Marmi, but we were just too bloody tired!