My addition to Professor Liulevicius' list, is the purported circumnavigation of the continent of Africa by the Phoenicians in 600 BC, an extraordinary feat of navigation and exploration for that time.
History's Greatest Voyages of Exploration.
The Scientific Voyage of Pytheas the Greek – The originator of the scientific expedition. First Greek to leave the known world. Supposedly circumnavigated the Britain, traveled into the Baltic and northern Europe, may have made it to Iceland.
St. Brendan—The Travels of an Irish Monk - sailed the Atlantic in a tiny leather boat—sought God and fled the world’s corruptions,
Xuanzang’s Journey to the West - Alarmed at inconsistencies in the Buddhist texts available to him, Xuanzang embarked on an illegal holy pilgrimage to acquire authoritative teachings…. achieved celebrity status, and became the central character in the greatest classical Chinese novel.
Leif Eriksson the Lucky.
Marco Polo Visits China.
Ibn Battuta—Never the Same Route Twice - left Morocco in 1325 to make a pilgrimage to the holy city of Mecca, but discovered a craving for spiritual travel and returned home 24 years later after covering 75,000 miles in the network woven by Muslim civilization.
Portugal’s Great Leap Forward - How and why did tiny Portugal, a poor country, take to the seas, round the continent of Africa, hijack the Indian Ocean, and create a global empire?
The Enigmatic Christopher Columbus .
Magellan and the Advent of Globalization .
Henry Hudson—Death on the Ice - tragic failure ending in mutiny, murder, and a mystery that endures to this day: Henry Hudson’s 1610 voyage in search of the Northwest Passage to Asia, funded by two of the first multinational corporations.
Captain Cook Maps the World .
Alexander von Humboldt—Explorer Genius .
Jefferson Dispatches Lewis and Clark .
Sir John Franklin’s Epic Disaster - the doomed expedition of Sir John Franklin, who disappeared in 1845 along with his crew while searching for the Northwest Passage.
Antarctic Rivalries – Norway beats Britain to the South Pole.
Source credit: Professor Vejas Gabriel Liulevicius, University of Tennessee