Global exploration started with the Portuguese discoveries of the Atlantic archipelagos of Madeira and the Azores, the coast of Africa, and the discovery of the sea route to India in 1498; and, on behalf of the Crown of Castile (Spain), the trans-Atlantic Voyages of Christopher Columbus between 1492 and 1502, and the first circumnavigation of the globe in 1519–1522. These discoveries led to numerous naval expeditions across the Atlantic, Indian and Pacific oceans, and land expeditions in the Americas, Asia, Africa and Australia that continued into the late 19th century, and ended with the exploration of the polar regions in the 20th century.
European overseas exploration led to the rise of global trade and the European colonial empires, with the contact between the Old World (Europe, Asia and Africa) and the New World (the Americas and Australia) producing the Columbian Exchange; a wide transfer of plants, animals, food, human populations (including slaves), communicable diseases and culture between the Eastern and Western Hemispheres. This represented one of the most-significant global events concerning ecology, agriculture and culture in history. The Age of Discovery and later European exploration allowed the global mapping of the world, resulting in a new world-view and distant civilizations coming into contact, but also led to the propagation of diseases that decimated populations not previously in contact with Eurasia and Africa and to the enslavement, exploitation, military conquest and economic dominance by Europe and its colonies over native populations. It also allowed for the expansion of Christianity throughout the world, with the spread of missionary activity, it eventually became the world's largest religion.
The Portuguese began systematically exploring the Atlantic coast of Africa from 1418, under the sponsorship of Prince Henry. Under Henry's direction, a new and much lighter ship was developed, the caravel, which could sail further and faster, and, above all, was highly manoeuvrable and could sail much nearer the wind, or into the wind. In 1488 Bartolomeu Dias reached the Indian Ocean by this route. In 1492 the Catholic Monarchs of Castile and Aragon funded Christopher Columbus's plan to sail west to reach the Indies by crossing the Atlantic. He landed on a continent uncharted by Europeans and seen as a new world, the Americas. To prevent conflict between Portugal and Castile (the crown under which Columbus made the voyage), the Treaty of Tordesillas was signed dividing the world into two regions of exploration, where each had exclusive rights to claim newly discovered lands.
In 1498, a Portuguese expedition commanded by Vasco da Gama reached India by sailing around Africa, opening up direct trade with Asia. While other exploratory fleets were sent from Portugal to northern North America, in the following years Portuguese India Armadas also extended this Eastern oceanic route, touching sometimes South America and by this way opening a circuit from the New World to Asia (starting in 1500, under the command of Pedro Alvares Cabral), and explored islands in the South Atlantic and Southern Indian Oceans. Soon, the Portuguese sailed further eastward, to the valuable Spice Islands in 1512, landing in China one year later. In 1513, Spanish Vasco Núñez de Balboa crossed the Isthmus of Panama and reached the "other sea" from the New World. Thus, Europe first received news of the eastern and western Pacific within a one-year span around 1512. East and west exploration overlapped in 1522, when a Castilian (Spanish) expedition, led by Portuguese navigator Ferdinand Magellan and later by Spanish Basque navigator Juan Sebastián Elcano, sailing westward, completed the first circumnavigation of the world, while Spanish conquistadors explored the interior of the Americas, and later, some of the South Pacific islands.
Since 1495, the French and English and, much later, the Dutch entered the race of exploration after learning of these exploits, defying the Iberian monopoly on maritime trade by searching for new routes, first to the western coasts of North and South America, through the first English and French expeditions (starting with the first expedition of John Cabot in 1497 to the north, in the service of England, followed by the French expeditions to South America and later to North America), and into the Pacific Ocean around South America, but eventually by following the Portuguese around Africa into the Indian Ocean; discovering Australia in 1606, New Zealand in 1642, and Hawaii in 1778. Meanwhile, from the 1580s to the 1640s, Russians explored and conquered almost the whole of Siberia, and Alaska in the 1730s.
Technological advancements that were important to the Age of Exploration were the adoption of the magnetic compass and advances in ship design. The compass allowed ships to sail shorter open water routes and avoid the dangers hugging of the shore, such as rocks and pirates. The compass had been used for navigation in China by the 11th century and was adopted by the Arab traders in the Indian Ocean. It spread to Europe by the late 12th or early 13th century.
The Chinese also made several important improvements in ship design, such as the sternpost rudder, multiple masts and lateen sails. These improvements gave greater maneuverability and allowed ships to sail at any time of the year. These new style ships were produced in Italian states between 1280 and 1330, resulting in boost in trade and connectivity between northern and southern Europe.