21st Century Museum of Contemporary Art

A circle of glass 112.5 metres across, set in the middle of Kanazawa next to a school, with four entrances and no front or back. SANAA designed it and won the Golden Lion at the Venice architecture biennale for it in 2004, and the building did what it was meant to do: it turned a city known for gold leaf and a feudal garden into a place people go for contemporary art.

The plan is deliberate. Galleries are boxes of different heights dropped inside the glass ring, and the corridors between them are free to walk. You can cut through the museum on your way somewhere else, sit on the lawn, use the library, and never buy a ticket. Around 2.5 million people a year come, which for a city of 460,000 is a remarkable number.

Leandro Erlich's swimming pool is the work everyone knows: from above you see people standing underwater fully dressed, and from below you are the person being looked at. Viewing it from beneath needs a paid timed ticket and it sells out early on weekends.

Two other permanent works are worth planning for. James Turrell's Blue Planet Sky is a square room with a square hole cut in the ceiling, open to the actual weather; sit there for twenty minutes and the sky changes colour in ways you had not noticed before. Outside on the lawn, Klangfeld Nr. 3 is a set of connected tubes children shout into.

Closed Mondays. Kenrokuen and Kanazawa Castle are a five-minute walk away, and doing the garden in the morning and the museum in the afternoon is the standard Kanazawa day.