There are hundreds of to do lists of the "hundred things to do before you die" sort. I have only one item and it is the Sistine Chapel, painted by Michelangelo. A One Man Show of gigantic proportions that has been around for 500 years and still makes ordinary beings like myself weak in the head. Photography at the Chapel is not allowed and I was happy to discover The Vatican has kept up with the 21st Century and put this online. If there is one thing that is worth the price of admission and a round trip ticket so you could see it in person, this is it. Below is a link to the Vatican website that hosts the tour online.
Sistine Chapel