TASK DEFINITION: Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.
PROBLEM: What is the name of the main thoroughfare in Barcelona, which runs from the Placa de Catalunya to the sea?

SOLUTION: barcelona

PROBLEM: Which English comedian has joined Amanda Holden as one of the judges on the current series of 'Britain's Got Talent'?

SOLUTION: britain's got talent

PROBLEM: Which British scientist lived at Down House, Kent, now in the care of English Heritage?

SOLUTION:
down house