Ciudad Perdida in Colombia predates Machu Picchu.

The Colosseum in Rome could hold between 50,000 and 80,000 spectators and had a retractable awning called the velarium.

Greenland is 80% covered by ice — if it all melted, global sea levels would rise about 20 feet.

The largest island in the world is Greenland.

The Sahara Desert spans across multiple countries in North Africa.

There is more water in Earth's mantle than in all the oceans on the surface.

There are abandoned cities hidden around the world that were evacuated suddenly.

The Sahara is the largest hot desert on Earth.

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