They can survive in lava for half an hour and accelerations of 3,400 Gs. Their beacons can be detected 20,000 feet beneath the waves. Most shocking of all - they aren't actually black! (They're bright orange = the least common colour in nature.)
Today it's the invention of the iconic Black Box (or Flight Recorder). We'll meet David Warren, the Australian who invented them. We'll learn how they work and try to fathom the strange fascination they hold.
Edited by Tom Delargy, Produced by Freddy Chick, Senior Producer is Charlotte Long