Beauty and agony often go hand in hand when it comes to jellyfish. However, in celebration of Jellyfish Day, we're offering up a sting-free series of jellyfish images straight from the National Geographic archives.
In the view above, biologist William Hamner makes his way through a lake in Palau filled with a kind of spotted jellyfish in the genus Mastigias.
These jellies are harmless to humans. Symbiotic algae living inside the creatures provide them with their food, unlike other jellyfish species that hunt for sustenance. The algae also give the jellies their greenish-brown hue.
—By Jane J. Lee, photo gallery by Kathy Moran
Diaphanous, Sometimes Deadly, Jellyfish Pictures From National Geographic's Archives
See some of our favorite jellyfish pictures in honor of Jellyfish Day.