WATCH: SpaceX launches one of the biggest rockets ever

When Falcon Heavy lifted off, it was the most powerful operational rocket in the world by a factor of two.

With the ability to lift into orbit nearly 64 metric tons (141,000 lb), Falcon Heavy can lift more than twice the payload of the next closest operational vehicle, the Delta IV Heavy, at one-third the cost.

Its first stage is composed of three Falcon 9 nine-engine cores whose 27 Merlin engines work together to generate more than 5 million pounds of thrust at liftoff, which is equal to approximately eighteen 747 aircraft. The only other vehicle to deliver more payload into orbit was the Saturn V, last launched in 1973.

Falcon Heavy was designed to carry humans into space and restore the possibility of flying missions with crew to the Moon or Mars.

One of the craziest things to watch for is the simultaneous landing of the booster rockets for future use.