British prime minister Theresa May invoked Article 50 of the Treaty on European Union, formally beginning the United Kingdom's withdrawal from the European Union.
Queen Elizabeth II granted royal assent to the Canada Act 1982, which ended any remaining constitutional dependence of Canada on the United Kingdom by a process known as patriation.
A group of farmers in the Chinese province of Shaanxi discovered a vast collection of terracotta statues (pictured) depicting the armies of Qin Shi Huang, the first emperor of China.