Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.

Who played Lionel Hardcastle in the TV series 'As Time Goes By'?
as time goes by

Which chemical element is named after the Latin for Copenhagen where it was discovered?
copenhagen

Fontwell Park, Fakenham, Ffos Las and which other horse racing venue in Great Britain begin with F?

britain