In Bermuda, for a few nights after the full moon between May and November, fireworms open up a natural nightclub on the surface of the ocean. First, female fireworms leave the seafloor to swim in illuminated blue-green circles at the surface. When the males see this, they get their glow on and head up, too. All at once, the males and females release their sperm and eggs in flashes of color beneath the waning moon, and then call it a night. Tourists regularly behold this flashy mating spectacle from the bridge at Ferry Reach Park, Flatts Inlet, or Hamilton Harbor.
Toyama Bay, Japan
Off the coast of Japan, currents bring thousands of firefly squid to the surface of the ocean during their spawning season, from March to May, each year. Fishing boats gather to take advantage and ensnare the creatures, whose photophores allow them to glow bright blue. Sightseeing boats filled with travelers show up just to observe as the glowing blue squid are brought in. Scientists believe they use their light for communication, attracting mates, and scaring predators. You can learn more about them at the area's Firefly Squid Museum, which claims, quite plausibly, to be the only such museum in the world.