Huge tech­ni­cal muse­um, on a for­mer rail­road depot, fea­tur­ing from ancient water and wind mills to com­put­er pio­neer Kon­rad Zuse’s inven­tions, a col­lec­tion of old to new vehi­cles of all types ‑bicy­cles, boats, trains, etc — and the inter­ac­tive Spec­trum sci­ence cen­ter with var­i­ous hands-on exper­i­ments. There’s an actu­al C‑17 Can­dy Bomber air­plane hang­ing on its faAade. The rail­road and aero­nau­ti­cal sec­tions are hard to beat.