The significance of the Treaty of Nanking in 1842 was that it marked the end of the First Opium War between the United Kingdom and Qing Dynasty China. Signed on August 29, 1842, the treaty imposed harsh terms on China, including the cession of Hong Kong to Britain, the opening of five treaty ports to British trade, and the payment of large indemnities. This treaty represented a critical moment in China's "Century of Humiliation," as it highlighted its weakening sovereignty under foreign pressure. The Treaty of Nanking set a precedent for subsequent unequal treaties, triggering significant social and political changes in China.