Bioluminesce, a form of chemiluminescence, describes the phenomenon whereby a living organism emits light as the result of a chemical reaction. The light — which is often an ethereal blue when seen at sea — was recently observed in Malibu, California, by photographer Jack Fusco.

The image was posted to Reddit on Sunday and received tens of thousands of reactions on the platform by Monday afternoon. Fusco, a nature photographer and touring musician, captioned the image: “Bioluminescence glowing under the Milky Way from a huge Malibu sea cave last night. Bucket list shot doesn't start to describe it!”

Bioluminescence glowing under the Milky Way from a huge Malibu sea cave last night. Bucket list shot doesn't start to describe it! from space

Reached for comment by International Business Times, Fusco explained how the image was made.

“After capturing the Milky Way in sea cave at Leo Carrillo in 2015, I had hopes of capturing the Milky Way in a similar fashion from the caves found at El Matador beach,” he said. “For this to work out, I need to plan around the tide lining up with the position of the Milky Way and for it to happen during the proper phase of the Moon.

“After that, it's just a matter of hoping the skies stay clear. I've been making trips back to this beach, about a 3-4 hour one way drive with traffic in hopes of making it happen, but never had all the elements line up. Either the tide wasn't quite low enough to safely shoot from the caves or the forecast was just wrong and there were no stars visible.”

A photo I took in Malibu of bioluminescence under the Milky Way from LosAngeles

Fusco told IBT that he made many trips back to the site to achieve the shot. While the results of his failed attempts were “discouraging,” he found success at the cave last week and was able to snap his “bucket list shot.”

“I timed my photos to start just a larger wave was about to crash I'd already be shooting,” he wrote of the experience on his blog. “I just need one strong wave to cause enough disturbance and cause the bio-luminescence to light up in the right spot. I took about 20 photos and then it happened right in the location I was hoping.”

He added: “It was an incredible night that I won't soon forget. Two years ago, thoughts of catching the Milky Way from inside a sea cave and getting a photo of bio-luminescence were two separate dreams.”

According to National Geographic, most bioluminescent organisms inhabit the ocean, and the blue-green light they produce is more easily observed in the deep ocean.

In a stunning video shared by National Geographic several years ago, the phenomenon was caught on camera at in the Caribbean Sea on a starry night. Using a Starlight camera technology, photographers were able to capture breathtaking bioluminescence below the ocean’s surface.