Name the bird that migrates from the North Pole to the South Pole and back...?

The Arctic tern holds the record for the longest migration of any bird, traveling approximately 71,000 km annually from its Arctic breeding grounds to Antarctic waters and back. This extraordinary journey allows it to experience two summers each year and maximize daylight hours for feeding. Swallows and cranes are migratory but travel much shorter distances, while penguins are non-migratory birds adapted to cold climates.