In 1942, after the surrender of the British in Singapore, Allied Prisoners-of-Wars (POW) were made to march from the city to Changi Prison and the surrounding barracks where they were interned. The POW Camps were overcrowded and life as described by those who were interned there was unbearable, multiple incidents including the Selarang Barracks incident took place. Civilians were also not spared, the Sook Ching massacre which targeted mainly the Chinese population, took place at multiple locations in Changi, most notably at Changi Beach Park. Thousands were believed to have been executed in these areas. It was during this time too that the Japanese were also involved in the planning and construction of Changi Air Base.