Mapo-gu's west side, built around an art school. Hongdae proper is the loud part — busking on the walking street, indie venues in basements, a Saturday artists' market that has run since 2002. Walk ten minutes northwest and it goes quiet: Yeonnam-dong is a low-rise grid of alleys either side of the Gyeongui Line Forest Park, a decommissioned railway now full of picnic blankets. Yeonhui-dong beyond it is quieter still and older-moneyed, with the neighborhood's best Chinese restaurant and its best bread.
Who it's for: People who want a night out that isn't a nightclub — this is the only district in Seoul where you can see live jazz, Korean indie rock and a vinyl-only gayo bar within one block. Cheap, serious eaters: the Bib Gourmand density here is real and the bowls are ₩9,500–14,000. Anyone who likes walking a city rather than ticking it off; the park, the alleys and the bookshops are the neighborhood's actual attraction.