Seoul—Korean for “capital”—had been a capital city in the region well before it adopted its apt name.

Settled in Paleolithic times six millennia ago, the region’s history as an urban center began with the initiation of Korea’s Three Kingdoms period.  As the capital of the Baekje Kingdom until 660, the city was then known as "Wiryesong". When Silla conquered its two rivals, Goguryeo and Baekje, the city was renamed once more to "Hanyang". The city later became the capital of the Goryeo Dynasty and was renamed "Namgyeong".

With the advent of the Joseon Dynasty, the capital was renamed once more to "Hanyang" and later "Hanseong".  The king of unified Korea, King Yi Song-Gye, brought his court—replete with shrines, palaces, hundreds of thousands of workers, and a heavily fortified wall—to modern-day Seoul in 1394. After a renaissance period in the 15th and 16th centuries, Korean civilization stagnated and the city was ransacked twice by Japanese invaders in 1592 and 1594. Korea turned towards isolation and later became known as "The Hermit Kingdom" by the West. 

The population steadily grew from over 100,000 to around 200,000 in the late nineteenth century, however, when the city began to modernize in the midst of competing foreign powers aiming to colonize Korea. Seoul became the first city in East Asia to have electricity, trolley cars, water, telephone, and telegraph systems all at the same time. In 1904, an American by the name of Angus Hamilton visited the city and said, "The streets of Seoul are magnificent, spacious, clean, admirably made and well-drained. The narrow, dirty lanes have been widened, gutters have been covered, roadways broadened. Seoul is within measurable distance of becoming the highest, most interesting and cleanest city in the East.”

However, it was too late and after Japanese agents assassinated Empress Myeongseong, Japan annexed Korea and renamed the city "Keijo". Korean as a language was made illegal, and Seoul citizens were also forced to change their names to Japanese equivalents. One of the city's palaces was converted to a zoo by the Japanese and most of Gyeongbokgung, at one time one of the largest palaces in Asia, was destroyed to make way for roads and buildings. By then, the city's population numbered nearly 750,000 persons.

When Korea regained independence after Japan's defeat in World War II, it served as the capital of South Korea (officially known as the Republic of Korea) and took on its current modern name of "Seoul". The Korean War (1950-1953), however, reduced the city to rubble, as it had been taken three times by North Korean forces, and it would take a couple decades of miraculous labor and development before the city would be more than what it had once been. This is known as the "Miracle of the Han River".

Today, Seoul is officially known as "Seoul Special City" and is its own administrative region. With over 10 million inhabitants, Seoul is one of the largest cities in the world in terms of population. In fact, the city proper's population make it the largest city in the OECD. The Seoul National Capital Area, which includes the Incheon metropolis and a large part of Gyeonggi province, has 24.5 million inhabitants making it the world's second largest metropolitan area after Tokyo.

Seoul hosted the 1988 Summer Olympic Games and the 2002 FIFA World Cup. It also hosted the 2010 G-20 Summit and was designated the 2010 World Design Capital. As one of the world's top 10 financial and commercial centers, it is home to some of the largest global corporations such as Samsung, Hyundai, LG, and SK. Seoul was the first city in the world to feature DMB and WiBro technology and has built the Digital Media City as a test-bed for advanced IT and multi-media infrastructure. It is the most technically advanced major city in the world.

After undergoing heavy industrialization, the city is now working to curb urban pollution and congestion. The nearly $1 billion Cheonggyecheon stream project, for example, is known as the largest single urban beautification project in history.