Whatever happened to Homo Aquaticus-the new breed of "humanfish" that were willing to surgically alter their bodies with artificial gills to allow them to breathe under water?

Famed undersea explorer Jacques-Yves Cousteau was convinced that Homo Aquaticus was next step in human evolution. "We are now moving toward an alteration of human anatomy," Cousteau told the World Congress on Underwater Activities in 1962, "to give man almost unlimited freedom underwater."

Cousteau was determined to prove humans could live and work underwater. In the early 1960s, he began a series of projects called Conshelf (or Continental Shelf Station). The submerged living quarters allowed aquanauts to stay undersea for up to a month. 

But creating an acceptable habitat was no easy task. Participants in Conshelf complained about loss of appetite, murky light, lack of privacy and their chirpy helium-inflected voices (for future expeditions, Costeau suggested creating "underwater Esperanto" with the "e" sound eliminated). 

Despite these obstacles, Cousteau viewed Conshelf as a success and later took home an Academy Award for the documentary World Without Sun that looked at his undersea experiment. Costeau's passionate advocacy helped create the impression that the depths of the ocean, like space exploration, represented the next great frontier. 

Public attention escalated. One of the star attractions of the 1964 World's Fair in New York was a General Motors exhibit which depicted citizens living underwater, farming the sea, drilling for oil, and vacationing at the Hotel Atlantis (pictured below).

But the public's interest in colonizing "inner space" proved to be short lived. Compared to the fascination of watching an astronaut stand on the moon, the idea of "humanfish" seemed whimsical at best; dangerous at worst. Some of the plans to colonize the deep seas were environmentally risky as well.

Today, a few stalwarts cling to the belief that living underwater is the only sane solution to solving the problem of overpopulation, Most people, like Cousteau, are simply attracted to the mysteries of the deep. "Man has only to sink beneath the surface and he is free," Costeau once explained about the allure of sea.

Until his death in 1997, Cousteau kept searching for new methods to allow humans to stay underwater; co-inventing the Aqua-lung in the 1940s and later testing new methods of scuba gear. Education was another of Clousteau's passions. "The conscious evolution of Home Aquaticus," he explained to the World Congress, was to "really learn about the sea."