Answer:
While Christopher Columbus and his crew of explorers were not the first Europeans to set foot on land in the western hemisphere (i.e., temporary Norse timber colonies of Leifsbudir and Straumsfjord circa 1000CE, in Newfoundland and Nova Scotia, Canada), they were the first such explorers to be heralded for their "discovery" of new lands to the west. The Viking explorations centuries earlier were accomplished by seafaring peoples with no written language or histories, so the knowledge of such North American settlements was lost until recent archaeological excavations and the so-called Vinland documents. Nevertheless, it is Christopher Columbus and his crew who are remembered as being the first Europeans to discover the new world. This discovery brought with it rapid colonization by the western European powers (namely, England, France, Spain, Portugal and the Netherlands), new trade commodities, advances in seafaring and supply preservation, and new contacts between cultures. Unfortunately, Columbus' discovery of the new world is also shrouded by the violence and death directly and indirectly inflicted on peoples indigenous to the western hemisphere.
Christopher Columbus' discovery undoubtedly changed history by opening up new lands for the European imperial powers to colonize and conquer, signaling the end of western hemisphere civilizations that were pushed to extinction or collapse, introducing products such as corn, potatoes, tobacco and chocolate to the rest of the world, and by laying the foundations for the new states of the western hemisphere.
