BEIJING, CHINA - AUGUST 20: Preparations continue at the China National Stadium on August 120, 2015 in Beijing, China.The 15th IAAF World Championships will be held in Beijing from August 22-30. (Photo by Michael Steele/Getty Images)
BEIJING, CHINA - AUGUST 20: Preparations continue at the China National Stadium on August 120, 2015 in Beijing, China.The 15th IAAF World Championships will be held in Beijing from August 22-30. (Photo by Michael Steele/Getty Images)