What it is: Agatha Christie's The Mousetrap, a murder-mystery play that opened in the West End in 1952.
Where it is: St Martin's Theatre, West Street, London WC2H 9NZ. Performances Tue–Sat evenings, with matinees on Thursday and Saturday.
Why it matters: It is the world's longest-running theatrical production. The original cast included Richard Attenborough and Sheila Sim. Audiences are still asked at curtain call not to reveal the identity of the murderer — a tradition Christie requested to preserve the ending for future productions.
