People watch as an acrobat rides his motorcycle around a circular track at an entertainment park set up outside a shrine in Rawalpindi, Pakistan, on June 19, 2013. (Photo by Muhammed Muheisen/Associated Press)

Mr. Zhong Hua, of Johns Hopkins University School of Medicine, took this image of the peripheral nerves (those outside of the brain) in an 11.5-day-old mouse embryo, magnified five times. (Photo by Zhong Hua)

Swedish photographer Paul Hansen won the 2012 World Press Photo award Friday for newspaper Dagens Nyheter with a picture of two Palestinian children killed in an Israeli missile strike being carried to their funeral.

Photo: In this photo provided on Friday February 15, 2013 by World Press Photo, the 2013 World Press Photo of the year by Paul Hansen, Sweden, for Dagens Nyheter, shows two-year-old Suhaib Hijazi and her three-year-old brother Muhammad who were killed when their house was destroyed by an Israeli missile strike. Their father, Fouad, was also killed and their mother was put in intensive care. Fouad's brothers carry his children to the mosque for the burial ceremony as his body is carried behind on a stretcher in Gaza City, Palestinian Territories, November 20, 2012. (Photo by Paul Hansen/Dagens Nyheter/AP Photo)

The provincial highest chimney collapses as it is demolished by explosives in Shenyang, Liaoning province, April 28, 2014. The 150-metre-high chimney used to be part of a local heating factory, according to local media. (Photo by Sheng Li/Reuters)

Two Bulgarian tourists pose in front of the Eiffel Tower in Paris on their last day in the capital on March 24, 2014. (Photo by Franck Fife/AFP Photo)

A soldier poses with a Hythe Mk III Gun Camera during training activities at Ellington Field, Houston, Texas in April of 1918. The Mk III, built to match the size, handling, and weight of a Lewis Gun, was used to train aerial gunners, recording a photograph when the trigger was pulled, for later review, when an instructor could coach trainees on better aiming strategies. (Photo by Harry Kidd/WWI Army Signal Corps Photograph Collection via The Atlantic)

An Indian white tiger cools off in a pond in its enclosure at Chhat Bir Zoo on the outskirts of Chandigarh on May 22, 2016. Temperatures have soared to a scorching 51 degrees Celsius in one Indian city, meteorologists said, with the ferocious heat setting a new national record. Northern Phalodi wilted as the mercury reached a new high on May 20, equivalent to 123.8 Fahrenheit, beating a 60-year-old record. (Photo by Shammi Mehra/AFP Photo)

Riot security forces clash with demonstrators as a motorcycle is set on fire during a protest against Venezuelan President Nicolas Maduro's government in San Cristobal, Venezuela May 29, 2017. (Photo by Carlos Eduardo Ramirez/Reuters)