A visitor stands in front of a portrait taken by artist Bruce Gilden at the “Masters of Photography” exhibition at the Photokina trade fair in Cologne on September 20, 2016. The fair for the photographic and imaging sector, that is running from September 20 to 25, 2016, presents products from image capture, image processing and storage to image output. Photokina also includes a program of events with congresses, workshops, symposiums and photography exhibitions. (Photo by Patrik Stollarz/AFP Photo)

Dancers perform a routine at the Renault display at the Beijing International Automotive Exhibition in Beijing, Tuesday, April 26, 2016. (Photo by Mark Schiefelbein/AP Photo)

Samburu tribesmen stand during the Maralal Camel Derby, Kenya, August 15, 2015. Maralal, a small, arid town about an eight-hour drive north of the Kenyan capital Nairobi, holds an annual camel festival, bringing together members of the Samburu, Turkana and Pokot semi-nomadic cattle-herding tribes. (Photo by Goran Tomasevic/Reuters)

Yan Mengjie sits on a boat as she poses for photos near Erhai Lake in Dali Bai Autonomous Prefecture, Yunnan province, China on June 16, 2019. Erhai is one of China's biggest freshwater lakes and a backdrop to the city of Dali, which drew 47 million visitors last year, more than triple the number in 2010. Hotels and homestays have sprung up along a 31-mile (50-km) stretch of lakeside road to accommodate tourists. But officials ordered some hotels demolished after President Xi Jinping during a 2015 visit called for the lake to be protected. (Photo by Tingshu Wang/Reuters)

A three-seater Toyota Kikai concept car is displayed during the 2016 CES trade show in Las Vegas, Nevada January 8, 2016. (Photo by Steve Marcus/Reuters)

Gun enthusiasts look over Smith & Wesson pistols at the NRA Annual Meetings & Exhibits on May 21, 2016 in Louisville, Kentucky. About 80,000 visitors are expected to attend the three-day event. (Photo by Scott Olson/Getty Images)

Promotional staff dressed in outfits of animation characters use a mobile phone at the Global Mobile Internet Conference (GMIC) 2015 in Beijing, China, April 28, 2015. (Photo by Kim Kyung-Hoon/Reuters)

A robot Ecce by the Robot studio is pictured at the world's largest industrial technology fair, the Hannover Messe, in Hanover April 13, 2015. (Photo by Wolfgang Rattay/Reuters)