In bodies of water around the world, bioluminescent creatures light up like a Christmas tree when disturbed, producing an electric blue glow. If you’re lucky enough to have been to Vaadhoo Island in the Maldives, you’ve probably seen them.

The Maldives are not unique in their glimmering waters, but they do tend to shine a bit more brightly. The bioluminescent plankton here maintain their glow for longer than the average animal, ensuring that visitors get a good show. In fact, the neon lights are so amazing that some travelers plan their entire vacations around the bioluminescent high season.

What is bioluminescence?

The glow on Vaadhoo Island is caused by plankton, but they’re not the only thing that shines. In fish alone, there are over 1,500 known species that luminesce—and that’s not counting all of the other marine creatures like jellyfish, sea stars, and sharks that light up.

While most luminescent creatures live in a warm water environment, there are several that live on land. The most familiar, of course, is the firefly—but there are dozens of others, like the railroad worm and even the millipede.

In a nutshell, bioluminescence is light produced by a chemical reaction within a living thing. Every reaction requires two chemicals, luciferin and either luciferase or photoprotein. Luciferin is the chemical that actually produces the light and determines what color it will be.

Those colors and their brightness can vary greatly depending on the type of animal and where it lives, but most marine creatures tend to be somewhere on the blue-green spectrum. Some of them emit light continuously, while some only shimmer when disturbed.

All of them glow for very specific reasons, although it’s not the same for every creature. For some, it is to hunt prey. For others, to find mates. And yet others use it as a defense mechanism.

What makes the Vaadhoo plankton glow?

These particular plankton seem to light up as a reaction to stress. It’s a defense mechanism meant to draw predators away from whatever they’re currently doing and toward the creature that’s trying to eat them. It’s rather ingenious!

While some creatures require a special food or another animal to make their glow, the Vaadhoo plankton (called dinoflagellates) create their own luciferin. Their light, like most other luminescent creatures, is a cold light—meaning that less than 20 percent of the light produces heat or radiation.

Where else can you see a glowing ocean?

If you want to see a bioluminescent sea yourself, you don’t need to make a trip halfway around the world. There are plenty of locations where the animals glow, casting beautiful blue light on the ocean. Luckily, most of them are lovely vacation destinations.

Some of the best spots include Puerto Rico, Jamaica, San Diego, Australia, Vietnam, and Thailand. No matter where you live in the world, one of them is bound to be close enough for a quick weekend away! Just be sure to go in season.