The FBI videotaped themselves blowing up a Nissan Pathfinder in order to demonstrate how big the explosion would have been if attempted terrorist Faisal Shahzad's Times Square car bomb had actually worked. So, how big? Pretty big!
The video was taken in a field in Pennsylvania, which looks sort of like Times Square, five centuries ago, pre-Pop-Tarts cafe. The New York Daily News describes the footage as "chilling". Sure! It is "chilling," insofar as it is a video of an actual bomb blowing up, instead of an incompetently-constructed mess of sugar-based fertilizer, firecrackers and alarm clocks, which is what was inside the Pathfinder that Shahzad parked in Times Square in May.
On the other hand: Check out that explosion!