A woman waits to hear about her sister, a teacher, following a shooting at the Sandy Hook Elementary School in Newtown, Connecticut. A man killed his mother at their home and then opened fire inside the elementary school where she taught, massacring 26 people, including 20 children, as youngsters cowered in fear to the sound of gunshots reverberating through the building and screams echoing over the intercom. (Photo by Jessica Hill/Associated Press)

Evan Leversage, who is terminally ill with brain cancer, is greeted by a Christmas decorated dog with his mother Nicole Wellwood (L), and his father Travis Leversage (2nd R) in St. George, Ontario, Canada October 24, 2015. Evan Leversage is a seven-year-old boy who has been living with inoperable brain cancer since he was two years old. His family has organized a Christmas celebration in October complete with a full parade, in case Evan does not live to celebrate his last Christmas day on the traditional date of December 25, according to local media. (Photo by Mark Blinch/Reuters)

In this November 18, 2014 photo, Murshida, 12, sits on the lap of her mother Marjina as the train leaves for their village in West Bengal, at a railway station in New Delhi, India. Six months ago, Marjina stepped off a train in New Delhi with her two children, hoping to find a better life after her husband abandoned them without so much as a goodbye. The family spent their days at a landfill picking through other people’s garbage to find salvageable bits to resell or recycle. After six months of poverty, illness and shame, they returned to that train station in New Delhi, headed back to an uncertain future to their hometown in West Bengal. (Photo by Altaf Qadri/AP Photo)

Grey seal pup “Nikolaus” licks a window at the seal enclosure in Friedrichskoog, Germany, 19 December 2014. The pup was abandoned by his mother and would not have a chance at survival without human help. Nikolaus will be fed at the enclosure for two to three months until he has reached the minimum weight of 45 kilograms for being released. (Photo by Daniel Reinhardt/EPA)

A Nepalese mother applies make up to her daughter dressed as the living goddess Kumari as they wait for Kumari puja to start at Hanuman Dhoka temple, in Kathmandu, Nepal, Wednesday, September 14, 2016. Girls under the age of nine gathered for the Kumari puja, a tradition of worshiping young prepubescent girls as manifestations of the divine female energy. The ritual holds a strong religious significance in the Newar community that seeks divine blessings to save small girls from diseases and bad luck in the years to come. (Photo by Niranjan Shrestha/AP Photo)

A 6-week old Fennec fox, the smallest species of foxes, and a native to the Sahara desert in Africa, looks as its mother eats in the Ramat Gan Safari Park near Tel Aviv, Israel, Sunday, November 6, 2016. Sagit Horowitz, the safari spokeswoman said four Fennec foxes were born about six weeks ago. (Photo by Ariel Schalit/AP Photo)

The fourth annual BigPicture Natural World Photography Competition aims to celebrate the diversity of life on Earth, and encourages people to protect and conserve it. Here: “The Salmon Catchers”. Terrestrial Wildlife. To capture this view of a mother grizzly bear and her cub, photographer Peter Mather set up a camera trap on a log that he knew the bears tended to traverse while fishing for salmon, in the Yukon River watershed in Canada. (Photo by Peter Mather/BigPicture Natural World Photography Competition 2017)