Sai Yeung Choi Street () are two streets in Mong Kok, Kowloon, Hong Kong, namely, Sai Yeung Choi Street South (西洋菜南街) and Sai Yeung Choi Street North (西洋菜北街). Although officially two streets, local people seldom make distinction between them. They are separated by the Mong Kok Police Station. Sai Yeung Choi Street South is a popular hotspot for shopping and a tourist attraction. History The streets were built on watercress cultivation in a village, Mong Kok Tsuen (旺角村), in Mong Kok in 1924. The name Sai Yeung Choi is the Chinese name of watercress. As time went by, the village and fields were replaced by high-rise buildings. When the police station was built, the street was separated into two sections. In the late 1970s the Postmaster General suggested renaming the streets, appending "south" and "north", to reduce confusion. On 12 January 1979, the streets were renamed. In the 1970s, some buildings on Sai Yeung Choi Street were demolished to make way for construction of the Mass Transit Railway. Sai Yeung Choi Street has been the site of several criminal acts of objects and fluids being thrown from buildings. On 13 December 2008, two bottles of corrosive liquid were hurled from buildings, burning 46 people. On 16 May 2009, two bottles of corrosive liquid were thrown, injuring 30 people. The police increased the award for information leading to an arrest, while the Yau Tsim Mong District Council installed a CCTV system to help catch the perpetrator. A third acid attack occurred on 8 June 2009, injuring 24. A similar attack occurred on 9 January 2010 on nearby Temple Street. On 10 June 2014, a pedestrian was killed on Sai Yeung Choi Street after being hit by a swivel chair thrown from a rooftop by a mentally-ill Mainland Chinese who had been drinking. Sai Yeung Choi Street was a frequent site of demonstrations during the protracted 2014 Hong Kong protests. Sai Yeung Choi Street South Starting from Dundas Street in Yau Ma Tei, it runs north and meets major roads, Argyle Street and Mong Kok Road, and ends at the junction with Prince Edward Road West. This street is a hot spot for Hong Kong people. The section south of Argyle Street concentrates shops of electronic products at street level and upstair bookstores above. The busiest portion of the street was pedestrianised all week long in 2000. However, the Traffic and Transport