Quartier des Grottes sits just behind Cornavin station, but it feels less buttoned-up than much of central Geneva. The neighbourhood mixes everyday cafes, small markets, and alternative housing blocks, with the famous Schtroumpfs buildings providing the visual punch.
Those curving, colourful apartment blocks are the usual reason travellers wander in, and they are worth the detour if you like architecture with a sense of humour. Stay a little longer for the neighbourhood itself, which gives Geneva a more lived-in texture than the lakefront institutions.