Rain has a smell! The earthy scent after rain is called petrichor.

Lightning strikes somewhere on Earth about 40 to 100 times every second.

People in ancient Egypt made paper from a plant called papyrus.

The Moon has no air, so sound can't travel there.

Red blood cells travel all the way around your body in about one minute.

The Mariana Trench is the deepest part of the ocean — almost 7 miles deep.

The ancient Egyptians built the Great Pyramid of Giza more than 4,500 years ago.