London

London has one rule that changes how you visit it compared with any other European capital: national museums are free. The British Museum, National Gallery, Victoria and Albert, Tate, Natural History Museum: you go in with no ticket and no booking. That means the day should not be built around admissions to justify, but around distances — which in London are real, since the city is fifteen times the size of Paris.
That is why here you visit by neighbourhood rather than by scattered monuments. In one day you cover the Thames axis, from Westminster to the Tower. In three you add the royal west with its parks and the South Kensington museums, and the eastern markets with a boat trip down to Greenwich. In five there is room for Windsor and the green London of the hills, the London tourists never see.
Each itinerary tells you how long every stop takes, how many minutes to the next one, what it really costs, how the Underground’s contactless payment works, and what to do when it rains — which in London is not a hypothesis.