Daejeon (tɛd͡ʑʌn) is South Korea's fifth-largest metropolis, with a population of 1.5 million as of 2019. Located in the central-west region of South Korea alongside forested hills and the Geum River, the city is known both for its technology and research institutions, and for celebrating its natural environment, with most mountains, hot springs, and rivers freely open for public use. Daejeon serves as a hub of transportation for major rail and road routes, and is approximately 50 minutes from the capital, Seoul, by KTX or SRT high speed rail.
Daejeon (along with Seoul, Gwacheon and Sejong City) are collectively South Korea's administration hubs. The city is home to 23 universities and colleges, including Korea Advanced Institute of Science and Technology (KAIST) and Chungnam National University, as well as government research institutes, and research and development centers for global companies such as Samsung, LG, mostly located in the city's Daedeok Science Town.
Occupied by humans since the Stone Age, Daejeon was historically a collection of small riverside villages. Though the area had varying degrees of strategic importance depending on the period in history, it was largely undeveloped until its use as a rail hub from the early 1900s, during the period of Japanese occupation. From the 1980s, multiple national administrative functions were moved from Seoul to Daejeon, most of which are now located in the Daejeon Government Complex, resulting in another population increase. The city hosted the 1986 Asian Games, the Taejon Expo '93, the International Mathematical Olympiads in 2000, and was elevated to the status of Metropolitan City in 2005.
Daejeon is situated in a lowland valley with three major rivers eventually flowing into the Yellow Sea by way of the Geum river. The city is surrounded by several small mountains, and is located approximately south of Seoul and north of Busan, and east of the Yellow Sea. Daejeon experiences a monsoon-influenced, four-season climate with wet, hot summers and drier, cold winters.