5 Most Important Photos in History?

This morning as I was riding the subway to work, I looked up and saw an outdated advertisement for the Jeff Wall retrospective held at MoMA earlier this year. The ad's tagline read "Only at MoMA" or something to that effect. I thought to myself, isn't this same show going on at SFMoMA? Sure enough, it is.

Wall's (new?) work is also being shown in England at White Cube. There's a longish interview in the Telegraph that starts:

Jeff Wall is arguably the most important photographer on the planet. Phaidon recently published a book showcasing 1,000 masterpieces from more than 30,000 years of art history. It contained only one photographer. Rather than Atget, Brassaï or Cartier-Bresson, the panel of experts chose Wall...

Wall is rightfully modest about this assertion. Not to say that Wall's work is or isn't worthy, only that it's ridiculous that only one photo was selected to represent the medium. 'Course, one could say it's a johnny-come-lately art form (if its an artform at all). Still, to be proportionate by time frame, photography would rate at least four more examples. Based on volume, maybe the whole things should be photos.

If you had to pick 5 photographs that would represent the entire medium for a history of art, what would they be?