The US has the world's highest incarceration rate — 639 per 100,000 people.

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

The Nile Delta is one of the world's largest river deltas.

The Earth's crust is thinner beneath oceans.

The Great Wall of China spans thousands of miles.

Mount Everest is not the closest point to space — that distinction belongs to Mount Chimborazo in Ecuador, due to Earth's equatorial bulge.

The Sahara Desert was once much greener than it is today.

The Caspian Sea is technically the world's largest lake, covering 371,000 square kilometers.

Venice, Italy is built on 118 small islands connected by over 400 bridges and is slowly sinking.