National Technical Museum is a real time commitment — fit it in only if it's a priority.
Allow 2–3 hours.
The payoff is one specific room: the soaring multi-storey transport hall, with vintage aircraft hung overhead and rows of gleaming pre-war Tatra and Škoda cars, locomotives and motorbikes below — a real wow that lands across ages. Just as telling is the contrast in feel: while the castle is a security-line scrum, this place stays calm and uncrowded even on a wet afternoon, so you can actually linger. The catch: it's a tram ride out toward Letná, the labelling skews Czech and technical, and beyond the transport hall it's firmly a 'museum day' rather than atmospheric old Prague.