Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.
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Question: Which horse won the 2008 Grand National?

Answer: 2008 grand national

Question: Which legal drama starring Martin Shaw ran for six series on BBC TV from 2001?

Answer: martin shaw

Question: In which city would you find Victoria Peak, Victoria Harbour, Tai Mo Shan, Lantau Island, Cheung Chau, Lamma Island, Peng Chau and Tsing Yi Island?

Answer:
lantau island