Reuters South Africa-based photographer Juda Ngwenya who documented Nelson Mandela's historic rise to power died on Wednesday. Here: Prostitutes wait at a bar in a plush northern suburb of Johannesburg August 22, 2002. (Photo by Juda Ngwenya/Reuters)

Singer Rihanna prepares for a photoshoot with photographer Annie Leibovitz in Havana, Cuba, May 28, 2015. (Photo by Reuters/Stringer)

The Jet Propulsion Lab team's RoboSimian robot turns on a valve at a simulated disaster-response course during day one of the Defense Advanced Research Projects Agency (DARPA) Robotics Challenge finals in Pomona, California, June 5, 2015. (Photo by David McNew/Reuters)

Damir Sagolj has won Reuters photojournalist of the year for his 2016 work, which included documenting the deadly Philippine drug war and the North Korea congress. Here: A 17 year old girl lays dead next to her doll after she and her friend were killed by unknown motorcycle-riding gunmen, in an alley in Manila, Philippines early October 26, 2016. According to the police, a sign on a cardboard reading “Tulak ka, hayop ka”, which translates to “You are a (drug) pusher, you are an animal” was found with the body of girl's friend. (Photo by Damir Sagolj/Reuters)

People on inflatable boats enjoy the weather on the Lake Lucerne in Sisikon, Switzerland, August 5, 2018. (Photo by Denis Balibouse/Reuters)

Ayah, 37, weeps as she is embraced by a police officer during a demonstration against the Danish face veil ban in Copenhagen, Denmark, August 1, 2018. (Photo by Andrew Kelly/Reuters)

A cow is seen on land that used to be under water, at the Aculeo Lagoon in Paine, Chile, May 14, 2018. (Photo by Matias Delacroix/Reuters)

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. Image taken by NASA's Hubble Space Telescope. Released September 24, 2015. (Photo by Reuters/NASA/ESA/Hubble Heritage Team)