or log in
The diameter of our galaxy is about 100,000 light years; it contains more than 100...
The largest contiguous savannah in the world is in Africa. It covers about one-third of the...
Water is one of our key natural resources; we must protect it vigorously.
A glacier is a large body of ice in constant, slow motion down a hillside.
Wind, as an external force, plays an important role in shaping coastal areas and steppes.
Tectonic plates can move in relation to each other.
This lesson introduces you to the world of minerals.
Karst formations include dolines and dripstones.