What is banji jumping?

Answer 1

Did you mean Bungee Jumping?

Bungy jumping (or bungee jumping) is the sport that originated from New Zealand and was created by maverick daredevil A J Hackett, and his original jump from a bridge in Greenhithe, Auckland. The sport denotes jumping from a tall structure while connected to a large rubber cord. The tall structure is usually a fixed object, such as a building, bridge, or crane; but it is also possible to jump from a movable object, such as a hot-air-balloon or a helicopter, that has the ability to hover over one spot on the ground; fixed-wing aircraft are clearly unsuitable because they only stay aloft when moving rapidly forward. The intense thrill comes as much from the free-falls as from the rebounds.[1] When the person jumps, the cord stretches to absorb the energy of the fall, then the jumper flies upwards again as the cord snaps back. The jumper oscillates up and down until all the energy is used up.

From Wikipedia.