Thank you, Jacques Cousteau.

It was just 67 years ago, in 1943, that young French Navy captain Jacques Yves Cousteau, working with an industrial engineer named Emile Gagnon, combined a primitive steel high-pressure air tank with a regulator adapted from airplane engines to create the Aqualung, the first Self Contained Underwater Breathing Apparatus (SCUBA).   Cousteau's invention marked a milestone in human history, and prompted for him a lifelong effort to popularize and protect the underwater realm through film, exploration, and his Cousteau Society.

The Blue Hole, seen from the air amid Lighthouse Reef, Belize.

One of the places Cousteau and his Calypso crew discovered and filmed in the 1970s was an obscure geologic wonder in the Caribbean Sea near tiny Belize (then British Honduras) called the Blue Hole.

Surrounded by extremely shallow water amid an atoll called Lighthouse Reef, the Blue Hole -- a vertical cylinder about 1000 feet across -- drops straight down at least 500 feet and, beneath its silt floor, probably several hundred feet more.  Created when dinosaurs still walked on dry land, the Blue Hole began as a cave in which forests of enormous stalactites and stalagmites -- literally 50 feet long and ten feet around -- formed over millions of years.  Then came ice ages and rising sea levels that finally caused the ceiling to collapse.

Today, entering the Blue Hole, a diver follows sheer rock walls down the first 100 feet before entering a chamber that expands outward beneath vaulted ceilings.  Here, swimming amid the ancient rock formations, one can peer out into the vast semi-darkness and see five different species of sharks circling endlessly.  Looking down, the bare walls extend only into darkness.

This past week, on a vacation in Belize, I has the chance to strap on a scuba tank and dive the Blue Hope myself for the first time.  I have been a sport diver since the early 1980s, but have never seen anything quite so awesome and humbling.  Adrenaline runs thick and bottom times go fast at depths of 140 feet.   (A quick plug for the fine local dive operation, Amigos Del Mar, in San Pedro, Ambergris Caye, Belize, that took us there.)

This summer, on Viral History, I will introduce you to some of my favorite ocean pioneers from the pre-scuba era who paved the way during the 1800s for Cousteau, Gagnon, and their milestone.  There's nothing better than a good sea story.   For now, I simply say thank you, Jacques Cousteau, for making the beauty, grandeur, and mystery of the ocean accessible, even to amateurs like me.