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

Who wrote `20,000 Leagues Under The Sea`?
20,000 leagues under the sea

In America, as what was Bill Shoemaker famous?
bill shoemaker

The novel 'The Hound of the Baskervilles', by Arthur Conan Doyle, is set on which English moor?

the hound of the baskervilles