Some 80 to 90 percent of undersea creatures make light — and we know very little about how or why. Bioluminescence expert Edith Widder explores this glowing, sparkling, luminous world, sharing glorious images and insight into the unseen depths (and brights) of the ocean.Some lucky animals are naturally endowed with bioluminescence, or the ability to create light. The firefly, the anglerfish, and a few more surprising creatures use this ability in many ways, including survival, hunting, and mating. Leslie Kenna investigates this magical glow - and our quest to replicate it.Widder shows a bioluminescent dinoflagellate. You can grow your own dinoflagellates at home. Here's how.David Gallo shows jaw-dropping footage of amazing sea creatures, including a color-shifting cuttlefish, a perfectly camouflaged octopus, and a Times Square's worth of neon light displays from fish who live in the blackest depths of the ocean.While the Earth’s oceans are known as five separate entities, there is really only one ocean. So, how big is it? As of 2013, it takes up 71% of the Earth, houses 99% of the biosphere, and contains some of Earth’s grandest geological features. Scott Gass reminds us of the influence humans have on the ocean and the influence it has on us.