From the "truth" behind the sinking of the Titanic to what really happened on 9/11, this look at some of the most popular conspiracy theories is a must-have for those eager to debate the "facts" of history   Delving a little deeper into 99 of the most intriguing conspiracy theories, this fascinating compendium looks at reasons to doubt each theory, and also reasons each theory could be true. In 1939 Glenn Miller stepped on board a small single-engined aircraft at RAF Beford and was never seen again—so what happened? In 1996 eyewitnesses reported a missile-like object streaking towards TWA Flight 800 before the jumbo exploded, killing all 236 people on board—what was it? In 1968 Robert F. Kennedy was gunned down by a politically-motivated assassin—or was he? Conspiracy theories have been around since records began. Easily dismissed as nonsensical rantings, in fact every conspiracy theory is grounded in truth, and that's when things get interesting.