A participant runs the Great Wall Marathon at the Huangyaguan section of the Great Wall of China, in Jixian of Tianjin, China May 19, 2018. (Photo by Jason Lee/Reuters)





Participants attend the Great Wall Marathon at the Huangyaguan section of the Great Wall of China, in Jixian of Tianjin, China May 19, 2018. (Photo by Jason Lee/Reuters)





Portuguese Adriele Silva (L) runs during the Great Wall Marathon at the Huangyaguan section of the Great Wall of China, in Jixian of Tianjin, China May 19, 2018. (Photo by Jason Lee/Reuters)





Participants run the Great Wall Marathon at the Huangyaguan section of the Great Wall of China, in Jixian, Tianjin, China May 19, 2018. The Great Wall Marathon, one of the world's most demanding long-distance races, was held along one of the new seven wonders of the world. (Photo by Jason Lee/Reuters)





Rescuers climb along a path to their service point for the Great Wall Marathon in Jixian of Tianjin, China May 19, 2018. (Photo by Jason Lee/Reuters)





Portuguese runner Adriele Silva run the Great Wall Marathon at the Huangyaguan section of the Great Wall of China, in Jixian of Tianjin, China May 19, 2018. (Photo by Jason Lee/Reuters)





Participants run the Great Wall Marathon at the Huangyaguan section of the Great Wall of China, in Jixian of Tianjin, China May 19, 2018. “It was very hard, it's my 25th marathon, my slowest and my most difficult one for sure, but amazing. I am glad I survived”, said Erin Skrettingland from the U.S. (Photo by Jason Lee/Reuters)





A participant wears a camera on his head during the Great Wall Marathon at the Huangyaguan section of the Great Wall of China, in Jixian of Tianjin, China May 19, 2018. (Photo by Jason Lee/Reuters)





A participant runs the Great Wall Marathon. The race, which first started in 1999, traditionally takes place on the third Saturday of May every year along the Huangyaguan pass near Tianjin city, China on May 19, 2018. (Photo by Jason Lee/Reuters)





Participants run the Great Wall Marathon at the Huangyaguan section of the Great Wall of China, in Jixian of Tianjin, China May 19, 2018. (Photo by Jason Lee/Reuters)





Rescuers help Portuguese runner Adriele Silva through a tower during the Great Wall Marathon at the Huangyaguan section of the Great Wall of China, in Jixian of Tianjin, China May 19, 2018. (Photo by Jason Lee/Reuters)





Participants run the Great Wall Marathon at the Huangyaguan section of the Great Wall of China, in Jixian of Tianjin, China May 19, 2018. (Photo by Jason Lee/Reuters)





Participants run the Great Wall Marathon at the Huangyaguan section of the Great Wall of China, in Jixian of Tianjin, China May 19, 2018. (Photo by Jason Lee/Reuters)





A participant runs through a tower during the Great Wall Marathon at the Huangyaguan section of the Great Wall of China, in Jixian of Tianjin, China May 19, 2018. (Photo by Jason Lee/Reuters)





Portuguese runner Adriele Silva gestures during the Great Wall Marathon at the Huangyaguan section of the Great Wall of China, in Jixian of Tianjin, China May 19, 2018. (Photo by Jason Lee/Reuters)