A glacier is a mass of ice that moves very slowly downhill. They are found at high altitude across the globe, even on high mountains close to the equator, and at lower altitude in high latitudes close to the North and South Poles. The formation of glaciers and the process by which they shape the landscape around them is called glaciation.
Glaciation in the last ice age
18,000 years ago ice covered about 30 per cent of the land in the world. In Britain, ice covered land as far as the Bristol Channel. During the last ice age the temperature remained below 0°C which allowed the ice to remain on the land all year.
Map of Europe during the last ice age