Glaciers are, in a nutshell, huge pieces of ice.
Read this article to learn of the creation and importance of glaciers. Glaciers exist in all parts of the world. They are formed when temperatures are right, but they also need a certain kind of atmosphere and precipitation. Certain areas of the world contain dry ground or tundra instead of glaciers, because precipitation and climate are not correct. Since hot summers also melt a glacier, glaciers tend to form in places where the temperature is the same all year round.