Swiss Museum of Transport (Verkehrshaus)

Far bigger than it sounds — hangars of locomotives, cutaway aircraft, a working signal box, and the Swiss Chocolate Adventure ride (a soft-serve-and-storytelling tour through Lindt's history). Easy 8-minute train ride from Lucerne station, or take the lake boat that has its own jetty. Allow at least three hours, or half a day if you add the planetarium and chocolate.