The waves are higher near beaches than in interior parts of the sea mainly because of the shallowness of the sea near beaches. The shape of the coast and surface features of the sea bottom near the coast also decide the height of the waves. In deep seas, the water in a wave moves in large vertical circles, without actually moving forward. Near the beaches such circulation is modified by the closeness of the bottom. This leads to increase in the height of the waves. Speed and direction of the wind, and the distance over which the wind is blowing are other factors that can further affect the height of waves. A strong wind can create huge waves even in mid sea.