From
杜牧 《
寄扬州韩绰判官》 (late Tang, ~830s), a quatrain sent to his old colleague Han Chuo in Yangzhou:
青山隐隐水迢迢,秋尽江南草未凋。二十四桥明月夜,玉人何处教吹箫 (Green hills dim, waters far; autumn ends in Jiangnan yet grass has not withered. On the Twenty-Four Bridges, bright moon night, where now is the jade beauty I taught to play the flute?).
二十四桥 is a famed Yangzhou bridge; the couplet made it eternal.