Photo courtesy U.S. Dept. of Defense
A U.S. Army officer plants 14 pounds of C-4 explosive on a command bunker in Bosnia-Herzegovina.
Twenty years ago, most people didn't have any idea what C-4 was. Recently, it has become an all-too-familiar term, popping up in newspapers and on television all the time. In October 2000, terrorists used C-4 to attack the U.S.S. Cole, killing 17 sailors. In 1996, terrorists used C-4 to blow up the Khobar Towers U.S. military housing complex in Saudi Arabia. In December 2001, a man smuggled similar material, hidden in his shoes, onto a commercial airliner. C-4 has also been used in many of the Palestinian suicide bombings in Israel and the Israeli-occupied territories.

In this edition of HowStuffWorks, we'll find out what this powerful material is and see how it can wreak such destruction.