If you've spent at least five minutes researching Budapest, you must have come across Szimpla Kert, Budapest's iconic ruin bar. Likely you're also familiar with the ruin bar (romkocsma) concept: makeshift bars inside dilapidated pre-war buildings of the Jewish Quarter, furnished with clearance sales furniture and exuding an inexplicably cool atmosphere.
Today, Budapest has many ruin bars, but Szimpla Kert, which pioneered the genre, is by far the best-known. Although it's no longer the offbeat bar it was when it opened in 2004 — you'll likely have to navigate through camera-wielding tourists to approach the bar — it's still worth a visit for the experience (prices have remained relatively reasonable). If daytime activities are more your speed, come for the Sunday morning farmers' market, taking place between 9 a.m. and 2 p.m.
A word to the wise: there's a still-functional mikveh, Jewish ritual bath, right next to Szimpla (#16). It's run by the local Orthodox community and serves as a reminder of the neighborhood's Jewish past.