Tsunami
A tsunami (from )  is a natural disaster which is a series of fast-moving waves in the ocean caused by powerful earthquakes, volcanic eruptions, landslides, or simply an asteroid or a meteor crash inside the ocean. A tsunami starts as a small wave and builds up into a larger wave., a tsunami starts suddenly. The waves travel at a great speed across an ocean with little energy loss. They can remove sand from beaches, destroy trees, toss and drag vehicles, houses and even destroy whole towns and cities. Tsunamis can even be caused when a meteorite strikes the earth's surface, though it is very rare. A tsunami normally occurs in the Pacific Ocean, especially in what is called the ring of fire, but can occur in any large body of water like lakes and  seas.                                                                                                                                   If the slope of the coast is not steep, the water may pull back for hundreds of meters. People who do not know of the danger often remains at the shore.