I've studied this amazing building over the last four years in various art history and architectural history classes. It's a masterpiece of Baroque architecture and I was extremely disappointed when we walked into the building and realized it was virtually covered in scaffolding. After walking around a bit we discovered you could take an elevator to a platform at the base of the dome and view the fresco painted on the dome up close.
This sunburst of marble, alabaster, and gilt elements was exceptionally beautiful.
The elevator took us up to the base of the dome and then we realized you could walk up to the cupola via a set of narrow stairs built of scaffolding. Only ten people could be on the stairs at once, but there was no actual way to tell how many people were walking up or down the stairs. As we reached the top and could look out at the amazing views, you could feel the plywood rocking back and forth as other people made their way up, needless to say we quickly turned around and walked back down.
The ceiling of the cupola...
Being able to experience this building in this unique way was priceless... its amazing to think that the only other people that were able to see it in this way were the people who first built it.