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

Example Input: The Byzantine Empire is the term used since the 19th century to describe the Roman Empire of the Middle Ages, centred on its capital, where?
Example Output: byzantine empire

Example Input: Which current Broadway musical has a Japanese therapist character called Christmas Eve?
Example Output: christmas eve

Example Input: Which Glasgow-based sculptor, whose works include artificial trees and a leaning litter bin, won the 2011 Turner Prize?
Example Output:
2011 turner prize