NEMO Science Museum

NEMO is the building you've already noticed from anywhere near Central Station: a huge green-copper hull rising out of the Oosterdok as if a ship were surfacing under the city. Renzo Piano designed it in 1997 over the entrance of the IJ road tunnel — the building's slope literally mirrors the tunnel diving beneath it — and it holds the Netherlands' national science centre, descendant of a science museum lineage going back to 1923.

Inside is the best wet-weather family half-day in Amsterdam: five floors of hands-on everything, pitched at kids but shameless fun for adults — a working chain-reaction machine, a bubble floor where you stand inside a soap film, water-management tables (this is the Netherlands; the flood-control exhibit is practically civics), a chemistry lab with real experiments in white coats, and the teenage-holdover favourite about the science of puberty and attraction that Dutch parents treat with total matter-of-factness.

The insider fact: the roof is free. The stepped plaza on NEMO's back — a public square tilted twenty-two degrees — is open to everyone without a ticket, with water cascades, summer deck chairs, a café, and a panorama across the old harbour to the church towers that beats paying for a viewing platform. Locals use it as a park; at sunset it's one of the city's quietly great spots.

If you do buy museum entry, go at opening or after 2 PM on school days and work top-down from floor five. Twenty minutes' walk from Dam Square along the water, or one stop on any bus over the IJ tunnel; combine with the neighbouring Maritime Museum's replica East Indiaman if the harbour mood takes hold.