Yes, I believe the Vatican deserves that title!
Wow, the Vatican in Rome is just magnificent. It is HUGE - yes, that is all caps - and it is simply stunningly gorgeous. I could go on but I would run out of superlatives before I felt like I really got my point across! It is that amazing.
When you take a tour of the place, I believe you will constantly be saying WOW and OMG and all that sort of stuff. It's a jaw-dropper, literally. Plus, there are a million parts of it and they are all photogenic. It's a good way to spend an entire day - and yes you could spend that much there.
This is a quick snap I took after our tour, down the main aisle. It's just cavernous in there!