The entire population of Earth in 1 AD was around 300 million — roughly equal to the current population of the United States.

There are more than 17,000 islands in Indonesia — making it the world's largest archipelago country.

Australia is wider than the Moon — Australia is about 4,000 km across, the Moon's diameter is 3,474 km.

Antarctica is the windiest continent — wind speeds can exceed 200 mph.

Iceland runs almost entirely on geothermal and hydroelectric energy — it is one of the greenest countries on Earth.

The Earth's crust varies in thickness beneath continents and oceans.

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

The ocean contains structures larger than mountain ranges.

The city of Istanbul spans two continents — Europe and Asia.