Museum of Illusions, London

The Museum of Illusions on Tottenham Court Road is an indoor attraction built entirely around optical illusions, which makes it a straightforward answer to a wet afternoon in central London. Exhibits include the Ames Room, a vortex tunnel, kaleidoscope mirrors and a Number 10 Downing Street door illusion, alongside interactive games. Most visits take one to two hours, so it fits alongside something else rather than filling a day. It caters for families, school groups and private events.