Many early movies were recycled to recover the silver in the film. The Library of Alexandria - an ancient center of learning containing a copy of every book in the world - was eventually burned to the ground. Even now, at the turn of the 21st century, no comprehensive archives of television or radio programs exist.
But without cultural artifacts, civilization has no memory and no mechanism to learn from its successes and failures. And paradoxically, with the explosion of the Internet, we live in what Danny Hillis has referred to as our "digital dark age."