"He is before all things, and in him all things hold together."
This is a picture of the main rotor retention nut on an AH-1W Cobra helicopter. When properly torqued down, it holds the two main rotors in place. Were it to fail, the rotors would come loose and the aircraft would plummet to the earth. In fact, it is so strong and so secure that the eye on top of the nut can be used to connect a line from which the helicopter can be lifted up and carried wherever it needs to go in the event that it becomes unable to fly on its own.
Perhaps not surprisingly, it is also known as the