I'm not a Christian, and certainly not a Catholic. In fact, my beliefs fall pretty much opposite of what anyone could reasonably define as "spiritual," with the exception that I'm certain there's a troll living under the Fletcher Dr. bridge. And when it comes to art, my tastes lie with Richard Serra's monumental, twisted steel plates or Ellsworth Kelly's radiating colored shapes. Yet despite all of that, the greatest work of art I've ever seen, the one that I hope aliens find when they descend upon our dead civilization after following the electromagnetic trail of an ancient Red Lobster commercial, is Michelangelo's ceiling of the Sistine Chapel.
No photos of the chapel can prepare you for the real thing. Looking at an image of a single panel of the ceiling is like looking at a single frame of a movie, and looking at an image of the whole ceiling is like looking at that movie's print unspooled across a pool table. The scope of the work just can't be reproduced in two dimensions. But I've just discovered the Vatican's high-res virtual tour of the chapel, and it comes as close as possible.