The National Coach Museum is arranged so that you walk forward through three centuries of carriages. It starts with a plain seventeenth-century travelling coach with no springs at all, its body slung on leather straps, which tells you what a journey across Portugal actually felt like. It ends with the last royal carriages of the nineteenth century, upholstered, lamped and sprung. In between stand three that were never really vehicles.
Those three were sent to Rome and back for a single day's use in 1716, and they have been kept ever since. What is worth doing is walking round behind them, because the whole design points that way. The driver's end is plain and the rear is a stage, with carved figures leaning outward over the axle so that they read from below. The bodies hang on leather straps rather than sitting on the frame, which is what passed for suspension. Nothing in the museum after them tries the same thing again.