Victor Vasarely, the Hungarian-French father of Op Art, designed this hexagonal concrete building himself and filled it with forty-four monumental works that you walk straight into. The whole place is a single-artist museum at architectural scale — black-and-white grids the size of a wall, kinetic illusions that seem to bend toward you, retinal experiments that you cannot look at for long without your eyes giving up.
It is a strange, hypnotic, slightly wonky place. The Fondation lay neglected for decades and the restoration is still ongoing, which only adds to the sense that you are walking through an abandoned modernist church. About three kilometres west of the city centre — twenty minutes by city bus, or a hot walk on a summer day. Closed Mondays.