title: Nuclear-powered icebreaker
context: The icebreakers have also been used for a number of scientific expeditions in the Arctic. On August 17, 1977, Arktika was the first surface vessel in the world to reach the North Pole. Since 1989, some icebreakers have been used for Arctic tourist cruises.
question: What is the biggest icebreaker ship in existence?
answers: Arktika