The strangest conspiracy theory is that 9/11 was perpetrated by 19 Middle Easterners carrying box cutter.
These individuals managed to outwit the defenses of the greatest superpower in the world..
Without knowing much about how to really fly aircraft they were able crash them into two buildings in New York causing THREE (WT, WT2, WT7) structures to come down at almost free-fall speed.
And one of the worst of the Middle Eastern pilots was actually able to perform an amazing feat of aerial daring and crash into the Pentagon.
Truly amazing conspiracy theory with a really large following.