A Tibetan rider fires his weapon as he perfoms his riding skills at the Qinghai Yushu Horse Racing Festival on July 27, 2007 in Yushu County of Yushu Tibetan Autonomous Prefecture, Qinghai Province, northwest China. The Horse Racing Festival of Tibetan nomads in Yushu Prefecture falls in late July and early August on the Tibetan calendar. During the festival, various equestrian skills will be performed along with singing, dancing and costume shows. (Photo by China Photos/Getty Images)

A bakery worker rides a bicycle as he carries fresh bread on his head in Cairo, Egypt, February 9, 2016. (Photo by Asmaa Waguih/Reuters)

New parents Chrissy Teigen and John Legend are seen leaving Khloe Kardashian's 32nd birthday party held at Dave and Buster's in Hollywood, California on June 28, 2016. (Photo by Splash News)

Tomomi Ota visits a local shrine with her humanoid robot Pepper in Tokyo, Japan, 26 June 2016. Reaching 120cm in height and 28 kilograms in weight, Pepper does not enter in the category of portable robot. But those characteristics dont stop Tomomi Ota to take Pepper in a cart to stroll in her neighborhood, go shopping or even take the subway... (Photo by Franck Robichon/EPA)

A 1949 Porsche 356 SL is displayed during the Porsche Rennsport Reunion V at Laguna Seca Raceway near Salinas, California, September 26, 2015. The three-day reunion is billed by organizers as the world's largest gathering of Porsche racecars, renowned drivers, and Porsche collector cars. (Photo by Michael Fiala/Reuters)

Performers eat their lunch before the start of the New Year's Day Parade in London, January 1, 2016. (Photo by Kevin Coombs/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 villager watches as Mount Sinabung volcano erupts, in Kuta Tengah village, Karo Regency in Indonesia's North Sumatra April 1, 2015. The Indonesian volcano was dormant for 400 years before erupting in 2010. (Photo by Y. T. Haryono/Reuters)