永定河
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.