Natural History Museum, London

For a day that costs nothing to walk into and still leaves children wide-eyed, the Natural History Museum is unmatched. The cathedral-like Hintze Hall, with its suspended blue whale skeleton nicknamed Hope, is a genuine wow moment, and the Dinosaurs gallery, complete with an animatronic T. rex, remains the headline draw for most kids. Beyond the big hitters there are the Volcanoes and Earthquakes gallery with its floor-shaking earthquake simulator, a wildlife garden, and hands-on discovery zones such as Investigate for younger visitors. General admission is free; popular timed special exhibitions and the winter ice rink are ticketed, and the cafes and cloakroom cost extra. It is extremely busy at weekends and in school holidays, so reserve a free timed-entry slot online and arrive early to beat the queues.