If I had to pick one building as the single most awe-inspiring work of humanity, it would have to be St. Peter's Basilica in Rome. I've been to a lot of famous churches in the world, but even St. Peter's worst completely outshines just about everyone's best. David and I visited St. Peter's on Christmas Eve.
The line to get in was somewhat long but moved quickly. It's funny to think that there was a time when you could just wander in and out of the church - but those days are long gone.
Had I realized that the church was going to be so sectioned off for mass, I would have visited the church sooner. On the morning of Christmas Eve, we could only walk through about half the church. However, any visit is worth it. St. Peter's never fails to impress.