Antarctica is the only continent with no native population and no permanent residents except researchers.

The United States Senate and House of Representatives form Congress.

Hawaii is moving toward Japan at about 3 inches per year.

The city of Jericho is one of the oldest known walled cities.

The Great Rift Valley in Africa may eventually split the continent in two, forming a new ocean in millions of years.

The Sahara Desert receives less rainfall than most regions.

Nan Madol is an ancient city built on artificial islets in Micronesia.

The Nile flows northward — it is one of the few major rivers in the world that flows from south to north.

The Ice Age featured massive glaciers covering large parts of Earth.