God, gold, and glory were the main motivations! "God" meant the desire to spread Christianity to non-Christian peoples. The Portuguese explorer Prince Henry the Navigator sponsored voyages partly to find Christian allies against Muslims. "Gold" meant the desire for wealth – spices (pepper, cinnamon, nutmeg), gold, silver, and silk. "Glory" meant national pride, personal fame, and the Renaissance spirit of discovery and achievement. European nations competed fiercely to claim new lands and build empires. This period transformed world history, connecting the Eastern and Western Hemispheres for the first time.

Prince Henry was called "the Navigator"! He sponsored over 50 voyages of exploration down the African coast. His school at Sagres brought together the best maritime knowledge of the time, including Italian navigation techniques, Arab ship designs, and Jewish cartography. Under his direction, Portuguese explorers discovered the uninhabited Azores and Madeira islands, and the Cape Verde islands. They learned how to sail against the wind using the caravel's lateen (triangular) sails. By 1460, Portuguese explorers had reached present-day Sierra Leone, paving the way for future voyages to India and the Spice Islands.

Columbus called the native people "Indians" because he thought he had reached the East Indies! His miscalculation – he underestimated Earth's circumference by about 25% – led him to believe Cuba was part of China and that the Caribbean islands were near Japan. He called the island he first landed on "San Salvador" (Holy Savior) and the native Taíno people "Indios" (Spanish for Indians). The name stuck for centuries. Columbus made three more voyages (1493, 1498, 1502), exploring the Caribbean islands and the mainland of Central and South America. He died in 1506, still convinced he had reached Asia.

Smallpox, measles, and influenza devastated the Americas! Native Americans had no previous exposure to these Old World diseases, so they had no immunity. Mortality rates were catastrophic – up to 90% in some regions. The population of central Mexico fell from an estimated 25 million before 1519 to about 1 million by 1600. This demographic collapse made European conquest much easier. In return, the Americas gave Europe syphilis (though this is debated). The Columbian Exchange also transformed diets worldwide: Irish cuisine became dependent on potatoes, Italian cuisine on tomatoes, and African cuisine on corn. Without the Columbian Exchange, we would have no pizza (tomatoes from Americas), no fries (potatoes from Americas), and no chocolate (cacao from Americas).

The Strait of Magellan is named after him! Magellan spent months searching for a passage through South America, hoping to find a western route to the Spice Islands (Moluccas). He discovered the strait in October 1520. The voyage across the Pacific took 99 days – with the crew suffering from scurvy (vitamin C deficiency), eating rat hides and sawdust, and drinking foul water. Magellan reached the Philippines in March 1521 but was killed in a battle with local chief Lapu-Lapu on April 27, 1521. The surviving crew under Juan Sebastián Elcano completed the circumnavigation, proving conclusively that Earth was round and larger than Columbus had thought.

Da Gama's voyage established a direct sea route to India! Before 1498, European access to Asian spices (pepper, cinnamon, cloves, nutmeg) required passing through Arab, Persian, Turkish, and Venetian intermediaries, who drove up prices. The Portuguese could now buy spices directly at their source, dramatically lowering costs. Da Gama's voyage also proved that the Indian Ocean could be reached by sailing around Africa – an idea that had been doubted. The Portuguese quickly established a trading empire in the Indian Ocean, seizing key ports in East Africa, India, and the Malay Peninsula. This marked the beginning of European colonialism in Asia.

Brazil lies east of the Tordesillas line! The line of demarcation was set at about 46°30′ W longitude. This placed the eastern bulge of South America (present-day Brazil) within Portuguese territory. When Portuguese explorer Pedro Álvares Cabral landed there in 1500 (on his way to India), Brazil became a Portuguese colony. That is why Brazilians speak Portuguese, while most of the rest of South America speaks Spanish. The treaty was respected by Spain and Portugal for much of the 16th century, but other European powers ignored it. The treaty was officially revoked in the 18th century.

Juan Sebastián Elcano completed the first circumnavigation! Magellan is often credited as the first person to circumnavigate the globe, but he did not survive the voyage – he only traveled halfway. Elcano took command after Magellan's death and successfully navigated the remaining route to Spain. The expedition proved beyond question that Earth was round, that the Americas were separate from Asia, and that the Pacific Ocean was vast. Lapu-Lapu, who killed Magellan, is celebrated in the Philippines as a hero who resisted foreign domination. The Victoria's return in 1522 was one of the greatest maritime achievements in history.

Hernán Cortés conquered the Aztecs! He landed on the Mexican coast in 1519, founding the city of Veracruz. He famously burned his ships to prevent his men from retreating. Cortés allied with the Tlaxcalans (traditional enemies of the Aztecs) and other native groups. When the Spanish arrived, the Aztec Empire ruled over millions of people but many subject peoples were unhappy and willing to rebel. Tenochtitlán, the magnificent capital built on an island in Lake Texcoco, fell after a 75-day siege. The modern Mexico City was built on its ruins. Cortés became governor of New Spain (Mexico), but died relatively unhonored.

Pizarro conquered the Inca Empire! The Inca Empire was the largest in the Americas, stretching 3,400 miles along the Andes. When Pizarro arrived, the empire was weakened by a civil war between brothers Atahualpa and Huascar for control after their father's death from smallpox. Atahualpa had just won the civil war when Pizarro captured him. The ransom room filled with gold and silver (measuring about 22 ft x 17 ft x 8 ft) contained an estimated 13,000 pounds of gold and 26,000 pounds of silver. Pizarro later died at the hands of his own countrymen – he was assassinated by rivals in 1541. The Spanish melted down the Inca treasure, destroying an enormous amount of irreplaceable art.