Seoul, officially the Seoul Special City, is the capital and largest metropolis of South Korea. With surrounding Incheon metropolis and Gyeonggi province, Seoul forms the heart of the Seoul Capital Area, home to roughly half of the country's population. Seoul is ranked as the fourth largest metropolitan economy in the world and is larger than London and Paris.

Strategically situated on the Han River, Seoul's history stretches back over two thousand years, when it was founded in 18 BCE by the people of Baekje, one of the Three Kingdoms of Korea. The city was later designated the capital of Korea under the Joseon dynasty. Seoul is surrounded by a mountainous and hilly landscape, with Bukhan Mountainlocated on the northern edge of the city. As with its long history, the Seoul Capital Area contains five UNESCO World Heritage Sites: Changdeok Palace, Hwaseong Fortress, Jongmyo Shrine, Namhansanseong and the Royal Tombs of the Joseon Dynasty. More recently, Seoul has been a major site of modern architectural construction – major modern landmarks include the N Seoul Tower, the 63 Building, the Lotte World Tower, the Dongdaemun Design Plaza, Lotte World, Trade Tower, COEX, and the Parc1 Tower. Seoul was named the 2010 World Design Capital. As the birthplace of K-pop and the Korean Wave, Seoul received over 10 million international visitors in 2014, making it the world's 9th most visited city and 4th largest earner in tourism.

Today, Seoul is considered a leading and rising global city, resulting from the South Korean economic boom - commonly referred to as the Miracle on the Han River - which transformed it into the world's 7th largest metropolitan economy with a GDP of US$635.4 billion in 2014 after Tokyo, New York City and Los Angeles. International visitors generally reach Seoul via AREX from the Incheon International Airport, notable for having been rated the best airport for nine consecutive years (2005–2013) by the Airports Council International. In 2015, it was rated Asia's most livable city with the second highest quality of life globally by Arcadis, with the GDP per capita (PPP) in Seoul being $39,786. Inhabitants of Seoul are faced with a high cost of living, for which the city was ranked 6th globally in 2017. Seoul is also an extremely expensive real estate market, ranked 5th in the world for the price of apartments in the downtown center. With major technology hubs centered in Gangnam and Digital Media City, the Seoul Capital Area is home to the headquarters of 15 Fortune Global 500 companies, including Samsung, LG, and Hyundai. Ranked sixth in the Global Power City Index and Global Financial Centres Index, the metropolis exerts a major influence in global affairs as one of the five leading hosts of global conferences. Seoul has hosted the 1986 Asian Games, 1988 Summer Olympics, 2002 FIFA World Cup, and more recently the 2010 G-20 Seoul summit.

Busan, formerly known as Pusan and now officially Busan Metropolitan City, is South Korea's second most-populous city after Seoul, with a population of over 3.5 million inhabitants. It is the economic, cultural and educational center of southeastern Korea, with its port—Korea's busiest and the 9th-busiest in the world—only about 120 miles (190 km) from the Japanese islands of Kyushu and Honshu. The surrounding "Southeast Economic Zone" (including Ulsan and South Gyeongsang) is now South Korea's largest industrial area.

Busan, formerly known as Pusan and now officially Busan Metropolitan City, is South Korea's second most-populous city after Seoul, with a population of over 3.5 million inhabitants. It is the economic, cultural and educational center of southeastern Korea, with its port—Korea's busiest and the 9th-busiest in the world—only about 120 miles (190 km) from the Japanese islands of Kyushu and Honshu. The surrounding "Southeast Economic Zone" (including Ulsan and South Gyeongsang) is now South Korea's largest industrial area.

Nagasaki is the capital and the largest city of Nagasaki Prefecture on the island of Kyushu in Japan. The city's name means "long cape" in Japanese. Nagasaki became a centre of colonial Portuguese and Dutch influence in the 16th through 19th centuries, and the Hidden Christian Sites in the Nagasaki Region have been recognized and included in the UNESCO World Heritage List. Part of Nagasaki was home to a major Imperial Japanese Navy base during the First Sino-Japanese War and Russo-Japanese War.

During World War II, the American atomic bombings of Hiroshima and Nagasaki made Nagasaki the second and, to date, last city in the world to experience a nuclear attack (at 11:02 a.m., August 9, 1945 'Japan Standard Time (UTC+9)').

As of 1 March 2017, the city has an estimated population of 425,723 and a population density of 1,000 people per km2. The total area is 406.35 km2 (156.89 sq mi).

Shanghai is one of the four municipalities under the direct administration of the central government of the Republic of China, the largest city in China by population, and the second most populous city proper in the world, with a population of 24.18 million as of 2017. It is a global financial centre and transport hub, with the world's busiest container port. Located in the Yangtze River Delta, it sits on the south edge of the estuary of the Yangtze in the middle portion of the East Chinacoast. The municipality borders the provinces of Jiangsu and Zhejiang to the north, south and west, and is bounded to the east by the East China Sea.

As a major administrative, shipping and trading city, Shanghai grew in importance in the 19th century due to trade and recognition of its favourable port location and economic potential. The city was one of five treaty ports forced open to foreign trade following the British victory over China in the First Opium War. The subsequent 1842 Treaty of Nankingand 1844 Treaty of Whampoa allowed the establishment of the Shanghai International Settlement and the French Concession. The city then flourished as a centre of commerce between China and other parts of the world (predominantly the Occident), and became the primary financial hub of the Asia-Pacific region in the 1930s. However, with the Communist Party takeover of the mainland in 1949, trade was limited to other socialist countries, and the city's global influence declined. In the 1990s, the economic reforms introduced by Deng Xiaoping resulted in an intense re-development of the city, aiding the return of finance and foreign investment to the city. It has since re-emerged as a hub for international trade and finance; it is the home of the Shanghai Stock Exchange, one of the world's largest by market capitalization.

Shanghai has been described as the "showpiece" of the booming economy of mainland China; renowned for its Lujiazui skyline, and museums and historic buildings, such as those along The Bund, as well as the City God Templeand the Yu Garden.

Shanghai is one of the four municipalities under the direct administration of the central government of the Republic of China, the largest city in China by population, and the second most populous city proper in the world, with a population of 24.18 million as of 2017. It is a global financial centre and transport hub, with the world's busiest container port. Located in the Yangtze River Delta, it sits on the south edge of the estuary of the Yangtze in the middle portion of the East Chinacoast. The municipality borders the provinces of Jiangsu and Zhejiang to the north, south and west, and is bounded to the east by the East China Sea.

As a major administrative, shipping and trading city, Shanghai grew in importance in the 19th century due to trade and recognition of its favourable port location and economic potential. The city was one of five treaty ports forced open to foreign trade following the British victory over China in the First Opium War. The subsequent 1842 Treaty of Nankingand 1844 Treaty of Whampoa allowed the establishment of the Shanghai International Settlement and the French Concession. The city then flourished as a centre of commerce between China and other parts of the world (predominantly the Occident), and became the primary financial hub of the Asia-Pacific region in the 1930s. However, with the Communist Party takeover of the mainland in 1949, trade was limited to other socialist countries, and the city's global influence declined. In the 1990s, the economic reforms introduced by Deng Xiaoping resulted in an intense re-development of the city, aiding the return of finance and foreign investment to the city. It has since re-emerged as a hub for international trade and finance; it is the home of the Shanghai Stock Exchange, one of the world's largest by market capitalization.

Shanghai has been described as the "showpiece" of the booming economy of mainland China; renowned for its Lujiazui skyline, and museums and historic buildings, such as those along The Bund, as well as the City God Templeand the Yu Garden.