Banqueting House

If one building explains why Britain ended up with a Parliament stronger than its monarch, it is this one. Charles I commissioned the Rubens ceiling inside to glorify his father and bolster the idea that kings ruled by divine right. In 1649 he stepped through a window of the same building onto a scaffold in the street and was executed, the climax of the Civil War between Crown and Parliament. Standing under Rubens's largest surviving work still in the place it was made for, with the execution site just outside, makes the argument vivid. Timing is the catch: Historic Royal Palaces opens it to the public only on selected open days and for a summer season, so check dates first. A new elevator gives step-free access to the main hall.