Under Exposed: Pekka Tuuri (Finland) – Great white shark, Isla Guadalupe, Mexico. “Isla Guadalupe is the world capital when it comes to observing great white sharks, but cage diving seriously limits the possibilities to take ‘fresh’ pictures. When I took this, the water close to the surface was quite milky, making photography very challenging. From out of the “mist”, I saw this great white shark lurking behind a school of fusiliers. I quickly focused on the shark and set a wide aperture to get focus blur on the fish, along with a fast shutter to avoid excessive motion blur”. (Photo by Pekka Tuuri/The Outdoor Photographer of the Year/The Guardian)

A country music fan cools off in the wind on the second day of the Stagecoach country music festival in Indio, California April 26, 2014. (Photo by Mike Blake/Reuters)

The entire cast perform during a production media call for Singin' In The Rain at Her Majesty's Theatre on May 12, 2016 in Melbourne, Australia. (Photo by Robert Cianflone/Getty Images)

A student falls asleep as she holds a book containing a portrait of China's late chairman Mao Zedong during a lesson at the Democracy Elementary and Middle School in Sitong town, Henan province December 3, 2013. In a remote part of central China, the day starts at the Democracy Elementary and Middle School with a pre-dawn jog, some revolutionary songs and then an activity long since forgotten at other schools: reciting quotations from Mao Zedong's famed “Little Red Book”. While the ruling Communist Party that Mao led continues to hold him in esteem as the leader of the Communist Revolution, his radical policies and teachings have been largely shelved since his death in 1976 in favour of a pro-market approach that has turned China from a backwater into the world's second biggest economy. The 120th anniversary of Mao's birth is on December 26, 2013. (Photo by Carlos Barria/Reuters)

The Berenson robot strolls among visitors during the exhibition “Persona : Oddly Human” at the Quai Branly museum in Paris, France, February 23, 2016. The Berenson robot, developed in France in 2011, is the brainchild of anthropologist Denis Vidal and robotics engineer Philippe Gaussier. Its programming allows it to record reactions of museum visitors to certain pieces of art and then use the data to develop its own unique taste, which allows “Berenson” to judge whether or not it likes a certain work of art within an exhibition. (Photo by Philippe Wojazer/Reuters)

Bikini-clad women ski as they are led by a car during a performance on the frozen Yenisei River outside Krasnoyarsk, Siberia, Russia, March 20, 2016. The performance, entitled “Siberian Spring's Strings” and created with the participation of artist Vasily Slonov, marked the day of spring equinox (vernal equinox), according to organizers. (Photo by Ilya Naymushin/Reuters)

“Cassowaries are large, flightless birds related to emus and (more distantly) to ostriches, rheas, and kiwis”, writes Olivia Judson in the September issue of National Geographic magazine. How large? People-size: Adult males stand well over five foot five and top 110 pounds. Females are even taller, and can weigh more than 160 pounds. Dangerous when roused, they’re shy and peaceable when left alone. But even birds this big and tough are prey to habitat loss. The dense New Guinea and Australia rain forests where they live have dwindled. Today cassowaries might number 1,500 to 2,000. And because they help shape those same forests – by moving seeds from one place to another – “if they vanish”, Judson writes, “the structure of the forest would gradually change” too. (Photo by Christian Ziegler/National Geographic)

A Hindu pilgrim feeds biscuits to an ox to seek blessing before heading for an annual trip to Sagar Island for the one-day festival of “Makar Sankranti”, in Kolkata, India January 10, 2017. (Photo by Rupak De Chowdhuri/Reuters)