What were the Opium Wars?

The First Opium War was a conflict between Britain and China—at that time ruled by the Qing dynasty—over questions of trade and sovereignty. It took place between 1839 and 1842. At the height of the opium trade through China, mainly facilitated by British merchants, many Chinese people were addicted; in an attempt to crack down on this, the Chinese government burned a huge quantity of opium. This created a hostile environment in which some British sailors killed a Chinese man. The British government objected to the Chinese trying British subjects in their courts, and war soon broke out. The war moved quickly, ending in the British capture of Nanking, and the Chinese were forced to cede Hong Kong to British powers.
The Second Opium War, fought between Britain and France against China, was fought from 1856–1860 and was essentially declared by Britain, and joined by France, as an excuse to try and extend trading permissions in China. By the end of the war, in which the European powers wreaked considerable destruction on Chinese ports, the Beijing Convention ceded many more trading ports and privileges to France and Britain.