Green Bay Packers' Johnathan Calvin rides a bike to NFL football training camp on July 27, 2017, in Green Bay, Wis. (Photo by Morry Gash/AP Photo)

Participants costumed as zombies try to catch hobby runners during the so-called Zombie-Run at the harness racing track Karlshorst in Berlin, Germany, 18 May 2014. The runners carry small flags in their belts which they have to get safely across the finishing line while the zombies try to steal them. The sporting event is based on the US television series “The Walking Dead”. (Photo by Soeren Stache/DPA)

Iraqis who have fled fighting between security forces and al-Qaida inspired militants in their hometown of Tal Afar arrive in a car at Germawa camp for displaced Iraqis, in a hot dusty plain in the largely-autonomous Kurdish area of Dahuk, 260 miles (430 kilometers) northwest of Baghdad Tuesday, June 17, 2014. (Photo by AP Photo)

A racegoer uses the camera on her phone to check her hair on the opening day of the Grand National Festival at Aintree Racecourse on April 3, 2014 in Aintree, England. The three days of racing attracts thousands of racegoers and fans from across the world. The meeting culminates with millions of pounds being wagered on the runners taking part in Europe's richest jump race, the Grand National. (Photo by Christopher Furlong/Getty Images)

The provincial highest chimney collapses as it is demolished by explosives in Shenyang, Liaoning province, April 28, 2014. The 150-metre-high chimney used to be part of a local heating factory, according to local media. (Photo by Sheng Li/Reuters)

A singer drinks from a huge bowl of beer on-stage as he pays tribute to the customers after performing at an entertainment club in Beijing, on May 8, 2014. (Photo by Jason Lee/Reuters)

Wang Zeyu, 4, a fee-paying enthusiast of kung fu, practises during a training class at a kung fu school near the Shaolin Temple April 10, 2005 in Dengfeng, Henan Province, China. Zeyu's father sent him to the school from his home in Jiangsu Province, thousands kilometres away from Dengfeng, when he was just 3 years old. And his father must pay 9,800 yuan (US$1195) for one year's tuition at the school, a huge amount for most Chinese. There are more than 80 kung fu schools that line the road from the city of Dengfeng to the Shaolin Temple with hundreds and thousands of young kung-fu lovers from all over the country and beyond studying here. All the schools use the Shaolin name to attract students as the Shaolin Temple is the birthplace of Chinese Kung Fu. (Photo by Cancan Chu/Getty Images)

Elephants spray tourists with water in celebration of the Songkran water festival in Thailand's Ayutthaya province, about 80 km (50 miles) north of Bangkok, April 9, 2014. (Photo by Rungroj Yongrit/EFE)