How do you move an object that weighs two and a half million pounds? In this episode of Worlds Toughest Fixes, Riley jumps in with a crew of the leading experts in moving BIG things. The challenge: move a mammoth, five-lane bridge two miles and drop it into place on a major U.S. Interstate highway in Salt Lake City. All without stopping highway traffic for a minute. And to add a little pressure, the placement must be accurate down to just a few inches. This isnt like parallel parking or backing your car into the driveway - you only get one chance at getting this right or everything comes to a screeching halt.