Rationale
A military drill is memorizing certain actions through repetition until the action is instinctive to the soldiers being drilled. Complex actions are broken down into simpler ones which can be practised in isolation so when the whole is put together the desired results are achieved. Such is necessary for a fighting force to perform at maximum efficiency in all manner of situations. However, depending on the army and the drills it adopts drilling may destroy flexibility and initiative in exchange for predictability and cohesion.
Recruits in most modern militaries are taught drill to teach them how to work and move as a team. In addition, formations are still used in riot control, where mêlée combat is still the norm.
Read more about this topic: Military Parades