The expedition sailed for days, finally coming upon a land covered in flat rocks, perhaps today's Baffin Island. They proceeded further south to the wooded Markland (Labrador) and at last arrived at the warm and fruitful Vinland (Newfoundland). The Vikings settled there among wild grapes and streams full of salmon, staying the winter. While there, it became obvious that the Viking from Spain had contracted the new and strange plague that was there, causing horrid blisters over the skin and high fevers. They cast him out of their settlement, making him seek help from the native Skraeling. From the sagas, it is believed the natives killed the man, but they became infected with what would later be called “smallpox” as it infected Europe.
Leif's expedition would return to Greenland with a wealthy cargo, even collecting a shipwrecked Viking and adding his wares to theirs. Earning the nickname “Leif the Lucky”, he would not return to Vinland, citing the dangerous peoples there. Other Vikings such as Thorvald, Karlsefni, and the treacherous Freydis would mount expeditions to Vinland, but no permanent settlement would ever take root. Meanwhile, the smallpox plague would sweep through the New World, wiping out some ninety percent of the population.
Nearly 500 years later, an Italian sailing for Spain would re-discover the lands west of the Ocean. Christopher Columbus would begin establishing trading posts and exploring. While the natives were at a severe disadvantage facing Conquistador firearms and steel, the sheer numbers of the population kept Spanish influence in check. The disastrous expedition of Cortes against the Aztec Empire would prove this, causing the deaths of hundreds of Spaniards and a military crackdown that would keep the Aztecs in power and limit relations with the Spanish to suspicious trade.
The Spanish gradually gained a sphere of influence over Middle and South America, but they could not establish the empire they hoped. Trade made them wealthy, but hardly more so than the Portuguese and their trade route around Africa as well as their trading posts in Brazil. In North America, the French would come out best, working well with the locals and harvesting furs for rich trade. The English made repeated attempts at settlement but were wiped out at Roanoke, Jamestown, and Charleston. Religious Separatists would found a plantation in Plymouth, which existed only at the mercy of the local tribes.
Eventually European technology would prove overwhelming, and the Americas would be carved up among the powers as they would do with Africa and Southeast Asia. Rule would be colonial rather than hardy frontiersmen in an empty land with tribes establishing treaties and forming military alliances while European maps gradually filled in gaps.
After the World Wars, industrialized Europe would grow tired of imperialism. Those colonies that could be kept were organized into commonwealths while the others were set into somewhat spontaneous political independence. Much of Aztec land would stand stolid, if backward, while the Incan princes maintained political domination over much of South America. In North America, tribes such as the Nez Perce, Cherokee, and Iroquois Confederation would form functional and profitable nations, other tribes in the Great Plains and Southwest found themselves plagued by warlords. Genocide in the Americas is a common issue brought before international committees on Third World charity.
In reality, small pox had not yet spread to the Vikings and would not have a conduit into the New World until the coming of the Spanish. The native population faced terrible plague that wiped out numerous tribes. This power vacuum allowed European powers to exert further control to establish cultural-revolutionizing empires and simply take up the now-empty land with wave upon wave of settlers.