北京动物园
In the north, Line 4 begins in Anheqiao, just beyond the Summer Palace, and heads south past the Old Summer Palace, through the university district and Zhongguancun, Beijing's high-tech silicon village, before turning east at the National Library of China and passing the Beijing Zoo en route to Xizhimen. After entering the 2nd Ring Road at Xizhimen, Line 4 resumes southwards at Xinjiekou and traverses the old city through Xisi, Xidan, Xuanwumen, Caishikou, and Taoranting Park. It passes the city's high-speed rail link at the Beijing South railway station before reaching the terminus at Gongyixiqiao. Construction began in 2004 but delays have pushed back the opening date by two years to 28 September 2009.