Photo: Wikimedia CommonsPerched on the bank of the Akerselva river below Grunerlokka, Blaa has been Oslo heart of live jazz and club culture since the late 1990s. Sunday nights bring the famous free jazz jam, weekends slide into DJ sets that run long past midnight, and in summer the riverside terrace is one of the best in the city. Check the listings before you go, arrive for the outdoor sundowners, then stay on as the music takes over inside.