large body of water at this point not a great idea. >> or is it magical? maybe not. she thinks not. when you do it for charity, maybe it's fine. in chicago this weekend, plenty of people were justified, i would say, in this strange human behavior because it was all for a good cause. diane pathieu from wls has more. >> reporter: a polar plunge for the history books in more ways than one. not only did a record number of plungers jump in to the freezing lake michigan water, but some big-name celebrities showed up. some without warning. nobody expected this. wearing a chicago fire department t-shirt pop star lady gaga took the polar plunge. she was dropped in the freezing lake michigan water while on the shoulders of her fiance taylor kinney. moments before, complete with a live bag pipe performance, wearing a blackhawks jersey, vince vaughn took the plunge. >> feels great. yeah. >> little chilly but fun. >> reporter: this is the largest