Delight in These 15 Photos That Capture the Exotic Undersea Lives of Jellyfish

They’re among the Earth’s simplest creatures, composed of 95 percent water, with no spines, brains or hearts, but jellyfish still manage to capture our attention. Older than the dinosaurs, members of this group have been around for 500 million years.

Floating through the seas like a feather caught in the wind, jellyfish are almost mythical with their bioluminescent abilities—but don’t get too close. Their tentacles are also defense mechanisms that can sting potential threats. If you need to really see them, take a look here—from a safe distance.