The May 16 military coup d'état was a military coup d'état in South Korea in 1961, organized and carried out by Park Chung Hee and his allies who formed the Military Revolutionary Committee, nominally led by Army Chief of Staff Chang Do-yong after the latter's acquiescence on the day of the coup. The coup rendered powerless the democratically elected government of Prime Minister Chang Myon and President Yun Posun, and ended the Second Republic, installing a reformist military Supreme Council for National Reconstruction effectively led by Park, who took over as chairman after General Chang's arrest in July.

South Korea, officially the Republic of Korea (ROK), is a country in East Asia. It constitutes the southern part of the Korean Peninsula and borders North Korea along the Korean Demilitarized Zone; though it also claims the land border with China and Russia. The country's western border is formed by the Yellow Sea, while its eastern border is defined by the Sea of Japan. South Korea claims to be the sole legitimate government of the entire peninsula and adjacent islands. It has a population of 51.96 million, of which roughly half live in the Seoul Capital Area, the ninth most populous metropolitan area in the world. Other major cities include Incheon, Busan, and Daegu.