A GLACIER is a slowly moving mass of ice that is formed over many years from the accumulation of snow. It is a large body of ice that moves slowly down a slope or valley, often forming rivers, lakes, and other landscape features as it melts. Glaciers are found in many parts of the world, including the polar regions, high mountains, and even some temperate regions. They are an important part of the global climate system, providing fresh water to many areas and influencing global sea levels.