They are relics of World War II and inconspicuous reminders of our colonial past. Once the temporary cradles of life in a much harsher time, many of the territory's air-raid tunnels have since been filled. With good instructions and keen eyes, however, some can still be found.
More than 20 kilometres of civilian air-raid tunnels lie beneath urban areas on both sides of the harbour. Although practically useless and almost forgotten, the tunnels were plagued with more controversies and scandals than any construction project today. Before they were even built, a debate raged.
'Was it practical? Would it do any good? A lot of people said it was a waste of time,' remarked Philip Bruce, a local military historian and member of the Royal Asiatic Society.
Indeed, the Government argued that civilians lacked enough time to take shelter in tunnels in the event of an attack and was reluctant to allocate money to build them.
Instead, precautions on how to secure homes were suggested and respirators sold at cost.
'Unofficial Chinese legislators [who did not hold government posts] criticised the Government for not providing shelters, and the press made a big deal of it too,' says another local historian, Colin Aitchison. 'But the fear of a Japanese attack on Hong Kong changed their minds. There was extreme urgency in the summer of 1940.' Tim Ko Keung, who has written a handful of books on Hong Kong's war history, including the English-language Ruins Of War published last year, said his interviews with local veterans presented a fragmented picture but few complained about the shelters.