War between China and Great Britain from 1839 to 1842. In this odd contrast to the modern War on Drugs, China tried to prevent British merchants from importing opium. After the confiscation and destruction of 20,000 chests of British opium (imported from India), British merchants appealed to their government. 16 British warships attacked Hong Kong and the surrounding areas in 1840, and in 1842 reinforcements allowed the capture of Shanghai and Nanking. The Treaty of Nanking was a capitulation by China, in which it ceded Hong Kong in perpetuity (but only a small portion of the eventual territories held by the UK, as the Hong Kong will tell you), opened its domestic market to British trade (while Britain remained mercantilist itself) and gave foreigners special rights in China.