TASK DEFINITION: Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.
PROBLEM: Which Chuck Berry song is performed by Marty McFly at the end of the film Back to the Future?

SOLUTION: back to the future

PROBLEM: The Trinity test site, outside of Alamogordo, NM, saw the first test of the atomic bomb on July 16, 1945. Headed by J. Robert Oppenheimer, what was the name of the project that developed the bomb?

SOLUTION: j. robert oppenheimer

PROBLEM: Which square in Cairo became the focal point for the uprising against President Mubarak?

SOLUTION:
cairo