Historical Explorations and Expeditions

James Cook is credited with the European discovery of Australia's eastern coast in 1770 during his first Pacific voyage. While Indigenous Australians had inhabited the continent for over 50,000 years and Dutch explorers had earlier visited parts of the northern and western coasts, Cook's expedition mapped the eastern coastline and claimed it for Britain. The other Cook names listed are unrelated - Thomas Cook founded a travel agency, and Alastair Cook is a modern cricketer.

Alexei Leonov was the first human to conduct a spacewalk on March 18, 1965, during the Voskhod 2 mission. He spent 12 minutes outside the spacecraft, proving humans could work in the vacuum of space. The name 'Leonov' in option D is the correct spelling.

Mount Everest was named after Sir George Everest, the Surveyor General of India from 1830-1843. The mountain was previously known as Peak XV before the Royal Geographical Society officially named it after him in 1865 to honor his work in surveying the Indian subcontinent.

Roald Amundsen, a Norwegian explorer, became the first person to reach the South Pole on December 14, 1911. He beat a British team led by Robert Falcon Scott by nearly a month. Amundsen was also the first to navigate the Northwest Passage and one of the first to overfly the North Pole.

Louis Hennepin, a Belgian Catholic missionary and explorer, is credited with discovering Niagara Falls in 1678 while exploring the Great Lakes region for New France.

Horatio Nelson was the famous British one-eyed Admiral who lost sight in one eye during the siege of Calvi. He became one of Britain's greatest naval heroes, winning victories at the Nile and Trafalgar.

Roald Amundsen from Norway was the first explorer to reach the South Pole on December 14, 1911. He beat Captain Robert Falcon Scott's British expedition by about a month.

Dave Kunst completed the first verified walk around the world between 1970-1974, walking 14,450 miles through four continents. He and his brother John started the journey; John was killed by bandits in Afghanistan, but Dave completed the circumnavigation alone. This was a remarkable feat of endurance and determination.

Charles Lindbergh made the first solo nonstop transatlantic flight in 1927, flying from New York to Paris in 33.5 hours in the Spirit of St. Louis. This achievement made him an international celebrity and revolutionized aviation. The flight demonstrated the potential for commercial air travel across oceans.

Robert E. Peary claimed to be the first to reach the North Pole on April 6, 1909, along with Matthew Henson and four Inuit guides. However, this claim has been disputed, with some evidence suggesting Frederick Cook may have reached it a year earlier, or that Peary didn't actually reach the exact pole. Despite controversy, Peary is widely credited in popular history.

Phu Dorji Sherpa of Nepal was the first person to climb Mount Everest without supplemental oxygen, achieving this feat on May 8, 1978. This was considered nearly impossible due to the extreme altitude and thin air. His achievement opened the door for 'alpine style' climbing at extreme altitudes. The question appears to be from an older source as there have been subsequent notable oxygen-less ascents.