This is the once-in-a-lifetime moment a British swimmer caught on camera a 2,000-strong shoal of rare migrating rays in Mexico. /VCG Photo

 Conservationist Jay Gittens initially thought the enormous “shadow” below the surface was a whale shark or humpback whale. /VCG Photo 

Amazed, Jay slipped into the waters off La Paz, Mexico, and moved with the enormous group of Pacific cownose rays. While the rays are not endangered, it is very rare to capture such a large group moving together. /VCG Photo