one of the most thrilling you'll ever see, and the one that will take your breath away the mo this is fabio in austria. he's hopped up on this railing in cold, snowy conditions. >> icy, icy conditions, nick. >> slippery. >> starts driving his bicycle over this enormous dam in austria. it's about 650 feet tall. >> no, i would get nervous cycling. not on the railing. nerves of steel. >> and what if he realizes in that moment that he's afraid of heights? >> this is just an incredible display of precision and talent done in a really, really inappropriately dangerous way. >>> from austria over to new york, where this group of guys have been thinking about doing something for years. finally on thanksgiving day they got up very, very e pulled off their dream, going where they are not exactly supposed to be. going into the water park. off-season water park with all these giant things to play around on. but guys look up at this and think, what? they had about two hours in this park before -- >> security guards got them. said, hey, get out of the park! >> never actually see any security guards. as so