Some jellyfish are bigger than a human and others are as small as a pinhead.
People in some countries eat jellyfish.
Jellyfish have been on Earth for millions of years, even before dinosaurs.
Jellyfish have no brain but some kinds have eyes.
Jellyfish are mainly made up of water and protein.
A group of jellyfish is called a smack or bloom.
Jellyfish are found in every ocean, from the surface to the deep sea.
Sources: National Geographic, Smithsonian
Art rendering: by S. Craig