Split-view of a killer whale at sunrise off the coast of Northern Norway. At least half of the world’s killer whale populations are doomed to extinction due to pollution of the oceans, a new study says. (Photo by Audun Rikardsen/Science)

Seth Casteel is an award-winning photographer and the New York Times Best Selling Author of Underwater Dogs. His new book, Underwater Puppies, was published September 16, 2014. Photo: “Underwater Puppies”: Popcicle. (Photo by Seth Casteel)

Maria Gabriela de Faria arrives at Nickelodeon's 28th annual Kids' Choice Awards at The Forum on Saturday, March 28, 2015, in Inglewood, Calif. (Photo by Chris Pizzello/Invision/AP Photo)

Photographer Gregg Segal travelled the world to document children and the food they eat in a week. Partly inspired by the increasing problems of childhood obesity, he tracked traditional regional diets as yet unaffected by globalisation, and ironically, found that the healthiest diets were often eaten by the least well off. (Photo by Gregg Segal/The Guardian)

A woman dives and pretends to ride a bike in Underwater Park in Pula, Croatia, August 1, 2017. (Photo by Antonio Bronic/Reuters)