A small section of the expanding remains of the Veil Nebula, a massive star that exploded about 8,000 years ago. The entire nebula is 110 light-years across, covering six full moons on the sky as seen from Earth, and resides about 2,100 light-years away in the constellation Cygnus, the Swan. (Photo by Reuters/NASA/ESA/Hubble)

In this September 10, 1977, file photo, from left, Hua Guofeng, Chinese Communist Party (CCP) chairman and Mao Zedong's immediate successor; Ye Jianying, CCP vice chairman and future ceremonial head of state; Deng Xiaoping, no formal titles at the time but soon to emerge as paramount leader during the reform era; Li Xiannian, CCP vice chairman and future president; Wang Dongxing, head of the leadership bodyguard unit who helped topple the Gang of Four, view the body of later Chinese leader Mao Zedong in Beijing. (Photo via AP Photo)

Durga Kami, 68, who is studying tenth grade at Shree Kala Bhairab Higher Secondary School, walks with his classmate Sagar Thapa, 14, as they head to school in Syangja, Nepal, June 5, 2016. (Photo by Navesh Chitrakar/Reuters)

Sun Model students pose for a photo during a training session at the school on March 31, 2014 in Phnom Penh, Cambodia. Having started in August 2010 with only three models, the Sun Model Agency and School is starting to make an impact in the fashion industry in Cambodia. (Photo by Omar Havana/Getty Images)

A mother bear takes a dip in the water to cool off in the warm summer sun but refuses to leave her three youngsters behind – so they climb aboard her back. (Photo by Jon Langeland/Solent News & Photo Agency)

John Malkovich as Marilyn Monroe in a re-creation of Andy Warhol's 1962 painting. The image is a part of the series, “The Malkovich Sessions”, by photographer Sandro Miller and on display at the Catherine Edelman Gallery in Chicago. Miller wanted to pay homage to the artists who influence his photographic career, and approached Malkovich with the idea of re-creating the famous portraits. (Photo by Sandro Miller/Catherine Edelman Gallery)

“Life in War” (FotoEvidence Press) by Iranian photographer Majid Saeedi is probably the only book about Afghanistan that doesn’t show images of war. For ten years his camera photographed daily life in the context of war. His photographs reveal the humanity of a people living through decades of war. Here: Afghan men escape increasing summer temperatures by wading in the Qarga reservoir on July 9, 2010 in a suburb of Kabul, Afghanistan. (Photo by Majid Saeedi/Getty Images)

Gloria Lincoln-Thompson carries her 9mm Smith & Wesson pistol in her waistband during a rally in support of the Michigan Open Carry gun law in Romulus, Michigan, in this April 27, 2014 file photo. (Photo by Rebecca Cook/Reuters)