The outcome of the Opium War between China and Britain, which took place from 1839 to 1842, was a decisive British victory and the signing of the Treaty of Nanking in 1842. The war stemmed from disputes over British opium exports to China, which had led to widespread addiction and social issues. The treaty forced China to open several ports to British trade, cede Hong Kong to Britain, and grant extraterritorial rights to British citizens. The outcome highlighted the power imbalance between Western powers and China, leading to the "Century of Humiliation," during which China faced numerous other foreign interventions and concessions.