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

A man from Dinka tribe holds his AK-47 rifle in front of cows in a Dinka cattle herders camp near Rumbek, capital of the Lakes State in central South Sudan December 14, 2013. (Photo by Goran Tomasevic/Reuters)

A resident walks past big waves spilling over a wall onto a coastal road in the city of Legaspi in Albay province, south of Manila on December 14, 2015, as typhoon Melor approaches the city. More than 700,000 people fled the central Philippines amid threats of giant waves, floods and landslides as powerful Typhoon Melor approached the archipelago nation, officials said December 14. (Photo by Charism Sayat/AFP Photo)

The 26th annual Visa Pour l’Image, the “Cannes Film Festival” of photojournalism kicks off, filling the French city of Perpignan with more than 3,000 of the world’s best photojournalists and photo editors, along with agencies from around the world. This year’s Visa Pour l’Image showcases 26 exhibitions around the city. Photo: Christians looting a Muslim shop in the “Combattants” district of Bangui. (Photo by Pierre Terdjman/Paris Match)

A mahout rides an elephant at Tad Sae Waterfall outside Luang Prabang, Laos July 31, 2016. Protected by the United Nations cultural heritage agency UNESCO, Luang Prabang is one of the most alluring places in the region – a city that evokes old-world romance that has gained a reputation as a travellers' Shangri La. (Photo by Jorge Silva/Reuters)

A general view of atmosphere at the annual VOLT Festival in Sopron, 208 kms west of Budapest, Hungary on August 16, 2016. (Photo by Mudra László/Rockstar Photographers)

An Armatix employee holds a “smart gun” by the company at the Armatix headquarters in Munich May 14, 2014. The gun is implanted with an electronic chip that allows it to be fired only if the shooter is wearing a watch that communicates with it through a radio signal. If the gun is moved more than 10 inches (25 cm) from the watch, it will not fire. A Maryland gun shop owner has dropped his plan to be the first in the United States to sell the so-called “smart gun” after a backlash that included death threats. (Photo by Michael Dalder/Reuters)

A person dressed as an astronaut walks past a man stopping traffic on a pedestrian crossing outside the Sydney Exhibition Centre September 13, 2014 where the science-fiction convention called “Oz Comic-Con” is currently being held. The two-day convention showcases “pop culture”, and includes appearances by actors from science-fiction movies and television shows. (Photo by David Gray/Reuters)