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

Which popular Doctor Who villains, it was revealed in 2011, are to be given 'a rest' by scriptwriters?
doctor who

Which American city has baseball-playing 'Dodgers'?
los angeles dodgers

The Bryce Canyon and Zion National Parks are in which US state?
bryce canyon national park