Bai Causeway, named White Sand Causeway in the Tang Dynasty (AD 618-907), was built to store water from the West Lake for irrigation. A poem was written about it by Bai Juyi, the then mayor of Hangzhou: “I love to stroll to the east of the lake the best, especially on White Sand Causeway in the shades of willows.” Actually, Bai Juyi had a causeway named “Revered Bai Causeway” built at that time, but later, when it was nowhere to be found, the White Sand Causeway was renamed Bai Causeway in commemoration of the preeminent “mayor” of Hangzhou.