Breaking into a car is generally a bad idea. That said, it could potentially be necessary to gain access to your own vehicle in an emergency, and it's actually much harder than you might think since most modern cars use tempered glass, which is much harder to crack. Still, it is possible... if you know the tricks.
The clip below comes from a National Geographic program called Hacking the System: Hack Your Car that airs on February 27 at 9:00 PM EST. It shows just what it takes to get through a car window and gives a handy hint on how to breach through tempered glass in a crisis. Scroll down to check out the video, but be sure to only try it on your own car.