Oceans are never still.  They are always moving.  The movement in the ocean is the waves.  Waves can be caused by large gusts of wind.  Whitecaps are the breaking waves.  After the waves break, they keep moving, traveling a long way from where they first originated.  Storm waves can get up to 111 feet above sea level.  Underwater earthquakes start some waves.  Waves that are started by these underwater earthquakes are called tsunamis. When tsunamis form, you cannot see them from the surface of the ocean.  They can race up to 500 miles an hour.  It takes about 20 minutes for a tsunami to reach its highest point and fall back down.  It can drown hundreds of people with its enormous crash. Tsunamis can wipe out a village in one wave.  Hurricane waves (caused by hurricane winds) can reach up to 130 feet.  The harder the wind blows the higher the waves get.  The shoreline formation depends on how big the waves are when they reach the shore.  When the waves crash, they crash with so much power that it takes away part of the land.  Sometimes when the waves crash, they bring mud and grass, and create new land. Sometimes the shoreline looks like big cliffs.  Waves can also shape beaches.  As well as forming beaches, waves can destroy and take part of them away.