You might find yourself thinking the lights on Michigan Avenue or your own street a pretty darn lovely this time of year. But they can’t hold a candle to the show nature puts on, especially off the coast of Egypt.

Divers and FiveDiveGear founders Lynn Miner and Steffen Beyer make underwater cameras for marine biologists, and occasionally film some dives of their own.

On their latest dive, the two captured the biological phenomenon of fluorescence of the coral reefs in the Red Sea near Dahab. No one really knows why fluorescence exists; biologists still can’t find a definite purpose or advantage it serves. When Miner and Beyer went on their midnight dive they brought along a blue light, between 450 ans 470 nanometers in wavelength, which excites the pigments in the fish, corals and other undersea creatures, causing them to give off photons and appear to glow.