Andrew Hepher, Vice President of Lubricants Technology, Shell unveils the Shell Concept Car in Beijing, China, Friday, April 22, 2016. Built as proof of energy efficiency that can be achieved with the latest technologies, Shell unveiled the concept car ahead of the bi-annual Beijing Auto Show where the world's top car manufacturers will showcase their own upcoming products. (Photo by Ng Han Guan/AP Photo)

A reveller dressed as Spider-Man takes part in a presentation at the top of a building during an annual block party known as “Enquanto isso na Sala da Justiça” (Meanwhile, in the justice room), one of the many carnival parties taking place in the neighbourhood of Olinda, Brazil February 7, 2016. (Photo by Ueslei Marcelino/Reuters)

Mohammad, a 13-year-old fighter from the “Free Syrian Army”, plays with a cat in Aleppo's Bustan al-Basha district, Syria October 28, 2013. Mohammad joined the Free Syrian Army after his father died during clashes with the Syrian regime. The gun he is using was his father's. (Photo by Molhem Barakat/Reuters)

A girl watches an acrobatic performance at the Longtan park as the Chinese Lunar New Year, which welcomes the Year of the Monkey, is celebrated in Beijing, China February 9, 2016. (Photo by Damir Sagolj/Reuters)

In this March 14, 2015 photo, tourists take pictures from a viewing area at Iguazu Falls in Brazil. From walkways and bridges, viewers can count 270 water falls almost 100 meters (330 feet) high. (Photo by Jorge Saenz/AP Photo)

A comedic photo of a cheetah appearing to find something hilarious by Dutton Robert for the Comedy Wildlife Photo Awards 2016, South Africa, April, 2012. (Photo by Dutton Robert/Barcroft Images/Comedy Wildlife Photo Awards)

Hillary Clinton waves to a selfie-taking crowd at a recent campaign event in Orlando, Florida on September 26, 2016. (Photo by Barbara Kinney/Hillary for America)

Women take a photo in the late afternoon sun during the Coachella Valley Music and Arts Festival on April 17, 2017 in Indio, California. (Photo by Carlo Allegri/Reuters)