In 1903 the Beijing–Hankou Railway arrived at Zhengzhou, and in 1909 the first stage of the Longhai Railway gave it an east–west link to Kaifeng and Luoyang; it later was extended eastward to the coast at Lianyungang, Jiangsu, and westward to Xi'an (Chang'an), Shaanxi, as well as to western Shaanxi. Zhengzhou thus became a major rail junction and a regional center for cotton, grain, peanuts, and other agricultural produce. Early in 1923 a workers' strike began in Zhengzhou and spread along the rail line before it was suppressed; a 14-story double tower in the center of the city commemorates the strike. On June 10, 1938, Chiang Kai-shek's National Revolutionary Army opened up the dikes retaining the Yellow River at Huayuankou between Zhengzhou and Kaifeng, in an effort to stem the tide of invading Japanese; however, the ensuing 1938 Yellow River flood also killed hundreds of thousands of Chinese.