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

Who had a hit album in 2010 with Can't Be Tamed?
can't be tamed

Which entertainer uses various names, including Puff Daddy, P. Diddy and Diddy?
p. diddy

One of the Wonders of the Modern World, The Catacombs of Alexandria are in which country?

alexandria