In a building (1990) by Swiss architect Mario Botta, Watari-Um stages exhibits that range from retrospectives of established art-world figures (such as Yayoi Kusama and Nam June Paik) to graffiti and landscape artists – with some exhibitions spilling onto the surrounding streets. 'Pair' tickets cost ¥1600 for two.
It's worth visiting just for the bookshop, On Sundays.