Before competing in the Mt Gaoligong Ultra in Southwest China last month, a group of runners from the United States had a glimpse of history connected to both countries.

A day before the start of the race in Tengchong, Yunnan province, they visited a war memorial dedicated to the Chinese People's War of Resistance Against Japanese Aggression (1931-45) and its effect on that part of the country. A special focus of the memorial is the Chinese Expeditionary Force and the battle for the key supply line linking Yunnan and Myanmar.

Another highlight is the history of the Flying Tigers, officially known as the American Volunteer Group.

Formed in 1941, the Flying Tigers flew supply missions over the dangerous "Hump" route from India to Kunming, Yunnan, and Chongqing during the war to support Chinese and American ground troops.

Bob Becker, a son of one of the US airmen, said the stories and artifacts in the memorial brought his family history into sharp focus.

As he listened to the guide's detailed account of how the Flying Tigers fought side by side with the Chinese people, and looked at the flight suits they had worn, the items they had used, and photos capturing their interactions with local people, Becker could not hold back his tears.

"It was very impressive and I got emotional. I felt a real connection because my father and my uncle both fought in World War II here," the 80-year-old said.

Becker said he was deeply touched by their spirit of selflessness, and their pursuit of a greater good and their recognition of the difference between right and wrong.

He expressed hope that more people from the US could come and see such stories firsthand, and understand the historic bond between the American and Chinese people.

After the visit, Greg Pressler, another US runner, emphasized the importance of remembering history. "When we forget history, we are at risk of repeating it," he said.

In an unstable world, it was incredibly moving to hear the stories of sacrifice, not only by the Chinese people, but also by those from abroad who came to assist them, Pressler said.

The memorial shows how powerful it can be when people set aside differences to help one another, he added.

David Green, another US endurance athlete, said that the visit provided a sense of optimism. Learning about a time when the two nations worked closely together, he said, offered a powerful reminder of what is possible.

"It renews my hope," he said, "that people, even from different backgrounds, can unite together."