A building like a Romanesque cathedral to nature: the NHM — the blue whale skeleton hung in solemn Hintze Hall, the dinosaur gallery's moving T-rex, and the earthquake simulator: king of London's family museums, free. Dinosaurs first on entry — their queue swells by holiday noon; the free Science Museum neighbors for the complete Kensington museum day; December-January sets the ice rink before it in London winter magic.