I wonder what would inspire someone to be part of a crowd of almost 20,000 naked people. Is it the desire to be part of something bigger than themselves? Or is it simply the desire to see lots of other people naked? Would you do this?

/Dario Lopez-Mills / AP
Thousands of naked people crouch in Mexico City's main Zocalo plaza during the massive naked photo session with U.S. photographer Spencer Tunick, early Sunday, May 6, 2007. According to the organizers, almost 20 thousand people took off their clothes.