Have you ever seen a "shooting star"? They are actually large chunks of rock and iron. When the, "shooting star" enters the atmosphere it is called a meteor. When they land they can create unique land forms and effect the geology of the land.
A large meteor hit this spot
Meteors can cause serious damage. In 2013 many Russian residents experienced a 10 ton meteor explode and evaporated at a height of around 30-50 km and injured at least 750 people. Only large meteors hit the earth because they don't burn up as fast as small meteors in the atmosphere. Even if a small meteor hit the earth it could still cause serious damage destroying cars bulding people and buildings.