Yongsan is in Seoul's geographic center, sandwiched between Seoul's two major cultural and economic centers, Gangnam and Jongno/Jung. The main area of interest here for travelers is Itaewon, the most international and foreigner-friendly neighborhood in Seoul, and one of the only places where you can find authentic Mexican, Turkish, Middle Eastern, and Indian food on the entire peninsula. It has Korea's only mosque, markets hawking souvenirs and cheap t-shirts, Turkish ice cream parlors, and a nightlife scene dominated by foreigners. This may be partly due to the presence of the nearby US military base, which is also stationed in Yongsan. Other attractions include the National Museum of Korea, the War Memorial Museum, and Yongsan Electronics Market, a huge building selling gadgets at a steep discount.
For the time being, Yongsan is relatively quiet compared to its northern and southern neighbors, with many one and two story houses covering rolling hills and the southern side of Namsan. However, things may soon change; the US military base is going to be moved to a different location by 2013, and talks are finalizing on the construction of Yongsan International Business District, an incredibly ambitious $28.8 billion project involving dozens of supertall skyscrapers, including a 665m centerpiece, making it the second tallest in the world after the Burj Khalifa in Dubai. If and when this project goes through, it would utter transform the urban landscape of Seoul, not to mention Yongsan itself.
National War Memorial, (전쟁기념관), (line 4 and 6, Samgakji stn). A museum about Korean military history and Korean War. Ancient, Middle Ages, and modern Korean weapons are on display. Also several fighter, bomber, and trainer aircraft which used during Korean War are on display.
The National Museum of Korea, (Metro Line 4 and Jungang Line, Ichon stn). Houses the best of the best collection of artifacts and relics from across Korea throughout different periods and dynasty. Also has some West Asian pieces from Japanese Governor-General of Korea. Closed every Monday.
I'Park Mall e-Sports Stadium, (Metro Line dark blue ,Yongsan stn). For a fascinating look into one of Korea's best subcultures, visit the top floor of the I'Park Mall neighboring Yongsan Electronics Market, where you'll find an e-Stadium. Here, professional video game players duke it out real-time on a enormous screen. Video games in Korea have been elevated into a sport, and there are professional leagues, mostly devoted to Starcraft, with matches that are, in fact, broadcasted on national television. Top players can earn hundreds of thousands of dollars a year in tournament winnings and sponsorships. A fascinating glimpse of Korea's new super-wired digital culture, and definitely one of the more interesting experiences to be had in Seoul.
Yongsan Electronics Market. (Metro Line dark blue ,Yongsan stn)Yongsan Station is in IMall which is another huge shopping mall with two storeys full of electronics. Without negotiating you can have cheaper prices when compared to amazon.com. Yongsan is one option in Seoul if you are looking for electronics goods. Made up of over 20 buildings housing 5000 stores, you can find appliances, stereos, computers and peripherals, office equipment, telephones, lighting equipment, electronic games and software, and videos and CDs. A lot of the products are bought in Japan and resold in Korea by dealers. The market has a reputation for fleecing foreigners, particularly due to its proximity to the Yongsan U.S. Army Base. Be wary as Koreans try to avoid Yongsan for their electronics needs and rely instead on internet shopping as sellers in Yongsan are not averse to ripping you off if you don't seem to know a lot about electronics. If you go, it's best to bring a Korean guide so you can ensure you're getting a good deal. The problem is no or very poor English. Only Korean warranty. Cash prefered. At IMALL they add 5% as tax when you pay by Visacard. At Yongsan Electroland it dependes on the seller. Up to 10% addition is possible.
Itaewon is Seoul's international district, with a wide variety of Western-styled venues to eat, drink and be merry.
Many Itaewon shops, restaurants and bars cater to foreigners, and English-speakers in particular.
Since many foreigners congregate there, Itaewon remains somewhat of a niche nightlife area for Koreans interested in a more international scene. A number of notable bars and clubs spot the area, both on the main street and in the nearby alleys. Long notorious for being somewhat seedy, with prostitutes plying their trade and alleged (gasp!) drug dealings, Itaewon has become cleaner and more gentrified in recent years. Of course, this is by Korean standards - Western travelers, especially American travelers, will wonder what all the fuss is about. Due to Itaewon's proximity to the nearby United States Army base, a large number of American military are found there in the evenings and weekends. However, the US army has decided to move the base to a location outside of Seoul within the next few years, so expect regular changes to the area.
Many bars in Itaewon celebrate Thursdays as Ladies' Night, which often means that women drink free before 12am. There are also a few gay bars located two alleys east of the main street, with a mix of clubs and places to drink.
Richard Copycat's All-American Diner, . Tons of great food and drinks. Serves authentic Buffalo wings and a great American breakfast (but not better than any of the five-star hotels in Seoul, just cheaper).
Geckos, (opposite Quiznos). A relaxed bar scene and good food. Very popular with GIs and expats (and prostitutes seeking customers).
Seoul Pub, has a pool table, darts and Guinness on tap. Badly needs a renovation.
Hollywood, is a sports bar with a pool table, darts, a golf arcade game and several TVs airing all kinds of sports. Reportedly Nigerians and American soldiers have been banned here.
Rocky Mountain Tavern, . A Canadian bar for expats living in Korea. Located east of the main intersection. They have weekly chicken wing specials. Go early.
The Wolfhound Irish Pub & Restaurant, . #in the alley behind Geckos across from Quiznos/Family Mart#. Serves a great selection of draft beers and hearty, homemade meals. Tuesday nights are buy one, get one free fish and chips.
Dillinger's. . #in the alley behind Geckos across from Quiznos/Family Mart#. Serves draught and bottled beers and good food. Wednesday night is Wing Night, where 10 wings go for 4,000 won. Sports played on a number of big screens, plus lounge/club upstairs.
3 Alley Pub, . Popular with the older expat crowd and located in an alley off the street near the Itaewon subway station. Great food and a wide selection of draut beers, though the owners can rub people the wrong way.
Sam Ryan's Sports Bar& Grill , . Located above 3 Alley Pub, this is the best sports bar in Seoul for North American sports. It shows numerous sports throughout the year on replay, sometimes live. Darts in the corner. A terrace in the back enables one to get away from all the noise. Rib night is Tuesday.
Helios. Seedy hip-hop club.
Metro. A lot of older expats and many Koreans hit up this joint. Only one Korean beer on tap, but free pool. The front #or right side when you go up the stairs# seems to be for the expat crowd, while the back #the left door when you go up the stairs# seems to be more hof style for the Korean crowd. They have the typical range of snacks available and free peanuts for beer drinkers.
Bless U is another older expat haunt. You better be good with your pool game or you'll be waiting in a long line to go again. Darts are also available. They have great popcorn and decent draft beers. It changed ownership last year and has been running a tight ship since.
The Rose & Crown. London-style pub with great fish and chips and interior decoration. Darts and sports on the big screen available.
Wit's End Itaewon.  Pretty cool and quiet place to have a few drinks. Great selection of bottled beer, wine, and scotch. Perfect place to take a date. The staff speaks great English and wide selection of music but she runs a tight ship. Check it out.
For some good house/trance music, try some places such as:
King Club. Gaudy and a tad sleazy. Located in a seedy part of the neighborhood.
Club Volume House/trance club, quite large and a excellent crowd on weekends. It is the best and most upscale club in the neighborhood.