Hong Kong pro-democracy campaigners have once again hit the streets en masse to mark one month of protests against the Chinese government's decision to only allow its hand-picked candidates to run for election as the territory’s top official in 2017. The roots of the demonstrations go back much further, though.

Hong Kong was under British rule for over 150 years. As the end of Britain's lease over the crown colony came into view in the late 1970s, the governments of Margaret Thatcher and Deng Xiaoping reached a formal agreement to hand back the territory to China in 1997.