The Sahara Desert has both sand dunes and rocky plateaus.

The Black Death of 1347–1351 killed roughly 30–60% of Europe's population.

The Aztec capital Tenochtitlan had a population of around 200,000 in the early 16th century, larger than most European cities.

The Australian lyrebird has such a powerful voice it can be heard over a kilometer away.

Africa is larger than China, India, the USA, and Europe combined.

The Amazon rainforest influences global rainfall patterns.

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

The Amazon River discharges more water than any other river.

The Sahara is the largest hot desert on Earth.