During World War II (China calls it the Anti-Japanese War) the Japanese invaded China and gained control of much of the eastern part of the country. The Nationalist government evacuated its capital from Nanjing to Chongqing. Some ministries and industries moved to Yunnan.
To maintain supply lines into western China the Nationalists built a road from Kunming (capital of Yunnan province) to connect with the famous Burma Road. But in 1942 the Japanese overan Burma and cut off this overland supply route.
By that time America was involved in the war. The Flying Tigers began flying supplies from India over the Himalayas into Kunming – 'Over the Hump'. At that time the route over 5,000-meter (15,000 foot) peaks was one of the world’s most dangerous.
During this period the US Office of Strategic Services (OSS), a forerunner of the Central Intelligence Agency (CIA) was involved in efforts to oppose the Japanese in China and Burma.
If you saw the film Julie and Julia you learned that Julia's husband Paul Child was a US State Department employee. The two met while Paul and Julia both worked for the OSS.
In 1945 OSS moved some of its personnel from India to China. Paul, Julia and other OSS personnel flew over the Hump. Betty MacDonald McIntosh was with Julia on the flight. In her book Sisterhood of Spies (US Naval Institute, 1998) McIntosh wrote, 'The turbulent, unpressurized flight on a rickety C-54 caused some people to get sick and others to pray. But Julia chatted with other passengers and read a book.'
It was while Paul and Julia lived in Kunming that they began their romance.