David Hall’s photographs of scenery and creatures off the coast of Canada in the Pacific Northwest portray serenity under the water, which belie the extreme challenges he faces to get his images. For each shoot, Hall wears a dry suit, a neoprene body suit that covers all of his body but his head and traps air inside to keep him warm. Water temperature in Canada’s British Columbia typically ranges between 45 and 50 degrees Fahrenheit. Photo: Moon jellyfish and cross jellies. (Photo by David Hall)

People gather as a crowd of sea lions lay on floating docks at Pier 39 in San Francisco, California May 4, 2015. Hundreds of sea lions began hauling out on the docks following the Loma Prieta earthquake of 1989, and face no natural predators at the pier. (Photo by Robert Galbraith/Reuters)

In this May 8, 2015 photo, sisters Zoraida Infante, left, and Graciela Trujillo pray on Fishermen's Beach before therapeutic swimming in the Pacific Ocean in Lima, Peru. Under overcast skies, the bathers practice thalassotherapy, which derives from the Greek “thalasso”, for “sea”, and draws on the ocean's healing properties. (Photo by Rodrigo Abd/AP Photo)

A woman stands next to a giant jandal on Tamarama Beach as giant sculptures are installed ahead of the “Sculpture by the Sea” exhibition in Sydney on October 19, 2016. Celebrating it's 20th anniversary, Sculpture by the Sea is the world's largest annual, free-to-the-public, outdoor sculpture exhibition. (Photo by William West/AFP Photo)

“I See Sea” by Photographer Dmytriy Dokunov. The frozen Black Sea. Scene of action: Odessa, Ukraine; January, 2012. (Photo by Dmytriy Dokunov)

A marine rescue worker from Sea World works in a joint attempt with his colleagues to help a juvenile humpback whale stranded at Palm Beach on the Gold Coast, in Queensland July 9, 2014. (Photo by Jason O'Brien/Reuters)

A truffle is seen on a table in Alba, north-western Italy November 11, 2013. Located in the heart of the Langhe – the hilly southern area of Italy's northwestern Piedmont region – Alba is the country's capital of white truffles, a variety of the prized fungus which grows underground. Truffles are found two to eight inches (5-20cm) below the ground near the roots of trees. They give off an odour which lasts for a limited period of time and can be detected with the assistance of well-trained dogs and experienced hunters. Output of white truffles, which are not cultivated and only grow naturally in forests, has fallen in Italy over the past few years, largely because climate change has brought a damaging mix of drought and torrential rains. (Photo by Stefano Rellandini/Reuters)