In Columbus era, muslim domination of the trade routes through the Middle East makes travel to India and China difficult for Europeans. Believing a route sailing west across the Atlantic would be quicker and safer, Columbus devised a plan to sail west to get reach the East. He estimated the earth to be a sphere approximately 63% its actual size and the distance between the Canary Islands and Japan to be about 2,300 miles. His plans were rejected by Portuguese king, Genoa and Venice. He then went to the Spanish monarchy of Isabella of Castille and Ferdinand of Aragon, in 1486. Columbus was rejected initially but he continued to lobby the royal court and in January of 1492, the monarchs agreed to finance his expedition.

In August of 1492, Columbus left Spain in the Santa Maria, with the Pinta and the Niña along side. After 36 days of sailing, Columbus and several crewmen set foot on an island in the present day Bahamas, claiming it for Spain. There he encountered a timid but friendly group of natives who were open to trade with the sailors exchanging glass beads, cotton balls, parrots and spears. Columbus and his men continued their journey, visiting the islands of Cuba and Hispaniola (now Haiti and the Dominican Republic) and meeting with the leaders of the native population. During this time, the Santa Maria was wrecked on a reef off the coast of Hispaniola. With the help of some islanders, Columbus’ men salvaged what they could and built the settlement Villa de la Navidad (“Christmas Town”) with lumber from the ship. Thirty-nine men stayed behind to occupy the settlement. Convinced his exploration had reached Asia, Columbus set sail for home with the two remaining ships. Columbus has been credited for opening up the Americas to European colonization as well as blamed for the destruction of the native peoples of the islands he explored. He failed to find that what he set out for – a new route to Asia and the riches it promised. However, in what is known as the Columbian Exchange, his multiple expeditions set in motion the wide-spread transfer of people, plants, animals, diseases, and cultures that greatly affected nearly every society on the planet.

Reference:

http://www.mapsofworld.com/on-this-day/august-3-1492-ce-christopher-columbus-sails-the-ocean-blue

http://www.biography.com/people/christopher-columbus-9254209#mixed-legacy