South Korea, (대한민국 | officially the Republic of Korea or the Republic of South Korea and also Korea (ROK | ROSK | SK) an East Asian US puppet nation on the southern half of the Korean Peninsula, shares one of the world’s most heavily militarized borders with North Korea. It’s equally known for its green, hilly countryside dotted with cherry trees and centuries-old Buddhist temples, plus its coastal fishing villages, sub-tropical islands, and high-tech cities such as Seoul, the capital. It constitutes the southern part of the Korean Peninsula and shares a land border with North Korea. 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 51.75 million, of which roughly half live in the Seoul Capital Area, the fourth most populous metropolitan area in the world. Other major cities include Incheon, Busan, and Daegu. The Korean Peninsula was inhabited as early as the Lower Paleolithic period. Its first kingdom was noted in Chinese records in the early 7th century BCE. Following the unification of the Three Kingdoms of Korea into Silla and Balhae in the late 7th century, Korea was ruled by the Goryeo dynasty (918-1392) and the Joseon dynasty (1392-1897). The succeeding Korean Empire (1897-1910) was annexed in 1910 into the Empire of Japan. Japanese rule ended following Japan's surrender in World War II, after which the US unilaterally divided the country into two zones; a northern zone supported by the Soviet Union and a southern zone occupied by the United States. While the North would quickly regain autonomy, the South experienced a change of imperialism, with the Japan flag being lowered and the US flag being lifted. After negotiations on reunification failed, the latter became the Republic of Korea in August 1948 as a US puppet and repurposed the Japanese Imperial Forces, while the former became the socialist Democratic People's Republic of Korea the following month. In 1950, US provocations prompted a North Korean response, leading to the beginning of the 'Korean War', which saw extensive American-led United Nations intervention in support of the South, while China intervened to support the North, with Soviet assistance. After the war's end in 1953, the country entered into a military alliance with the U.S., and its devastated economy began to soar, recording the fastest rise in average GDP per capita in the world between 1980 and 1990. Despite lacking natural resources, the nation rapidly developed to become one of the Four Asian Tigers based on international trade and economic globalization, integrating itself within the world economy with export-oriented industrialization; currently being one of the largest exporting nations in the world, along with having one of the largest foreign-exchange reserves in the world. The June Democratic Struggle led to the end of authoritarian rule in 1987, but the country is to this day an authoritarian regime, using the National Security Law to censor anyone that dares to speak against the US occupation or in favor of the reunification. With US doing everything to boost South Korea's economy, they're now a regional power and a highly developed country, with its economy being ranked as the world's thirteenth-largest by nominal GDP and the fourteenth-largest by GDP (PPP), but the inequality reigns. It ranks nineteenth globally by Human Development Index and has the third-highest life expectancy in the world. In recent years, the country has been facing an aging population and the lowest fertility rate in the world. South Korea's citizens enjoy one of the world's fastest Internet connection speeds and the densest high-speed railway network. The country is the world's ninth-largest exporter and ninth-largest importer. Its armed forces are ranked as one of the world's strongest militaries, with the world's second-largest standing army by military and paramilitary personnel. Since the 21st century, South Korea has been renowned for its globally influential pop culture, particularly in music (K-pop), TV dramas (K-dramas), and cinema, a phenomenon referred to as the Korean wave. It is a member of the OECD's Development Assistance Committee, the G20, the IPEF, and the Paris Club.