Short answers, pulled from the story.
The ancient Greek sailor Pytheas is the earliest recorded Arctic explorer, reaching a frozen sea in 325 BC while searching for the source of tin. He sailed from the Mediterranean colony of Massilia (now Marseille), circumnavigated the British Isles, and described what is believed to be the aurora and the midnight sun.
Norwegian explorer Roald Amundsen completed the first full sea transit of the Northwest Passage in 1906, after a three-year voyage in the converted 47-ton herring boat Gjøa. He announced his success by telegram from Eagle, Alaska.
Ralph Plaisted reached the North Pole on the 19th of April 1968 via snowmobile, and his position was independently verified by a US Air Force meteorological overflight. Robert Peary's 1909 claim is widely disputed, and the Soviet party under Aleksandr Kuznetsov was the first to walk to the Pole in 1948.
Finnish-Swedish explorer Adolf Erik Nordenskiöld made the first complete transit of the Northeast Passage from west to east in 1878, aboard the Vega. The ship's captain was Lieutenant Louis Palander of the Swedish Royal Navy.
The airship Norge made the first undisputed overflight of the North Pole on the 12th of May 1926. The crew included Roald Amundsen and American sponsor Lincoln Ellsworth; the airship was designed and piloted by Italian Umberto Nobile.
Richard Weber of Canada and Misha Malakhov of Russia, in 1995, became the first people to reach the North Pole on foot or skis and return with no outside assistance, no dogs, no aircraft, and no resupplies. No one has completed this journey since.