London, verdict by verdict

London earns its scale. This is not a walkable postcard city but a string of villages glued together by the Tube, and its great trick is how much of the best of it is free: the big museums, the markets, the parks, the Sky Garden's floor-to-ceiling view for the price of a timed ticket, and the pub culture that threads it all together. The Tower's Crown Jewels, Westminster Abbey's Lady Chapel and an evening Thames-and-Westminster skyline deliver the paid hits when you want them.

The punishments are planning and price. Beds cost brutal money year-round, the distance between things punishes a badly chosen base, the paid icon-view attractions are often the most skippable things on the itinerary, and queues run long at the Abbey, the Jewels and every timed-ticket freebie. Sky Garden's free weekend and sunset slots vanish within days of release, the Eye costs heavily per minute, and the city is simply contactless-everything now.

Give it four days minimum and accept you will not see it all: one anchor sight a day plus an evening neighbourhood is the winning pattern. First-timers do best near the river between Westminster and Tower Bridge; repeat visitors graduate to Shoreditch or South London. The Piccadilly line is the value airport run, Stonehenge goes early or goes crowded, and May and September hit the sweet spot between weather and crowd load.