Bombs, the pinnacle of all action movies! Bombs are a pretty basic idea, it is just a container filled with explosives that can be detonated. When these bombs go off they can cause a blast wave. The blast wave occurs when the explosion creates highly compressed air particles. The compressed air particles can in some cases travel faster than the speed of sound, creating a LOUD sound. This initial blast wave causes most of the damage. This kills someone as one part of their body is moving super-fast while the other part stays stationary, this can compress soft tissues and potentially stop your heart. The blast wave creates an area of high pressure rapidly expanding outwards at high velocities creating very strong winds.
This is an image of a blast wave, as it expands rapidly!