The Marco Polo Bridge or Lugou Bridge is a stone bridge located 15 km southwest of Beijing's city center in the Fengtai District. It bridges the Yongding River, a major tributary of Hai River. Situated at the eastern end of the bridge is the Wanping Fortress, a historic 17th-century fortress, with the Museum of the War of Chinese People's Resistance Against Japanese Aggression inside.

The Second Sino-Japanese War was the war fought between the Republic of China and the Empire of Japan from 1937 to 1945 as part of World War II. It is often regarded as the beginning of World War II in Asia. It was the largest Asian war in the 20th century and has been described as "the Asian Holocaust", in reference to the scale of Japanese war crimes against Chinese civilians. It is known in Japan as the Second China–Japan War, and in China as the Chinese War of Resistance against Japanese Aggression.