With over 10 million registered citizens, the city of Seoul is the most populated single city (excluding greater metropolitan areas) in the world that human civilization has yet known - see Rand McNally (ISBN: 0-528-83872-5). Its density has allowed it to become one of the most "digitally-wired" cities in today's globally connected ecomony. It also has more than 1 million registered vehicles which cause isolated traffic-jams beyond midnight.
This city was renamed from Hanyang (漢陽) to Hanseong (漢城) when it became the capital of the Joseon Dynasty[?] in 1394. It is now called Seoul, meaning capital in Korean. It has no Hanja and can only be written in Han-geul.
Originally entirely surrounded by a massive circular wall (a 20 feet high circular stone fortress) to provide security its citizens from wild animals such as the Korean Tiger, theives and attacks; only the South and East Gates still remain today. Each entrance was opened and closed each day, by ringing large bells, to allow traffic.
Urban and civil planning was a key concept when Seoul was first designed to serve as a capital in the 14th century. The Royal Palace of the Joseon Dynasty still remains in Seoul, and is currently being restored to its original form.
The wide road of Jongro, meaning "Avenue of Nobles" still remains today downtown. The two parallel back streets, on its North and South side, were used by those that occupied the lower class before Japan invaded Korea.