Seoul's World Cup Stadium was built as the centrepiece of the 2002 Korea/Japan World Cup. Asia's largest soccer-only ground seats 64,777 and has its own subway stop on Line 6 (World Cup Stadium Station), making it easy to reach from the city centre.
The FIFA 2002 World Cup Museum inside covers Korean football history through to the team's remarkable semi-final run, with signed memorabilia, replicas, and enough interactive gimmicks to hold your attention. A self-guided stadium tour (separate ticket) takes you down to the dugouts and through the players' tunnel — worthwhile for the access. Both cost around 1,000 won each.
Alongside the Han River just outside, what's claimed to be the world's largest fountain shoots water 202 metres into the air. Worth a detour if you're passing.
The stadium complex also houses a CGV cinema, sauna, supermarket, and the usual coffee chains. FC Seoul play their home matches here, and the atmosphere on match days bears little resemblance to the quiet of an off-season visit.