The Opium Wars (1839-1860) were pivotal conflicts between Britain (later joined by France) and China's Qing Dynasty, sparked by Britain's illegal opium trade to offset tea imports. The First War (1839-1842) ended with the Treaty of Nanjing, forcing China to cede Hong Kong, open five ports for trade, and pay reparations—marking the "unequal treaties" era and China's "Century of Humiliation." The Second War (1856-1860) escalated with the Arrow Incident, leading to the burning of the Summer Palace