I lived in Hong Kong for a couple of years in the 1970s and it was already more like the second photo. There were parts of the New Territories which were undeveloped but HK Island and the whole of Kowloon was pretty much wall to wall skyscrapers.A lot of the housing stock was built in the early 1970s to accommodate refugees from the Mainland and the population went from 3 million to 5 in the space of 20 years. It's grown by another 3 million since I was there!
Jonathan Callaway ● 1832d