According to Norse folklore, violent conflicts with the indigenous population ultimately made the Norse abandon those settlements. Extensive European colonization began in 1492, when a Spanish expedition headed by Genoese Christopher Columbus sailed west to find a new trade route to the Far East but inadvertently landed in the Americas. European conquest, large-scale exploration, colonization and industrial development soon followed. Columbus's first two voyages (1492–93) reached the Bahamas and various Caribbean islands, including Hispaniola, Puerto Rico and Cuba. In 1497, sailing from Bristol on behalf of England, John Cabot landed on the North American coast, and a year later, Columbus's third voyage reached the South American coast. As the sponsor of Christopher Columbus's voyages, Spain was the first European power to settle and colonize the largest areas, from North America and the Caribbean to the southern tip of South America. Spanish cities were founded as early as 1496 with Santo Domingo in today's Dominican Republic. Other powers such as France also founded colonies in the Americas: in eastern North America, a number of Caribbean islands, and small coastal parts of South America. Portugal colonized Brazil, tried early (since 1499) colonizing of the coasts of present-day Canada, and sat for extended periods on the northwest bank of the River Plate (including it in the Brazilian region). This was the beginning of a dramatic territorial expansion for several European countries. Europe had been preoccupied with internal wars, and was only slowly recovering from the loss of population caused by the bubonic plague; thus the rapid rate at which it grew in wealth and power was unforeseeable in the early 15th century. Eventually, the entire Western Hemisphere came under the ostensible control of European governments, leading to profound changes to its landscape, population, and plant and animal life. In the 19th century alone over 50 million people left Europe for the Americas. The post-1492 era is known as the period of the Columbian Exchange, a widespread exchange of animals, plants, culture, human populations (including slaves), communicable disease, and ideas between the Pan-American and Afro-Eurasian hemispheres following Columbus's voyages to the Americas. In the context of the United States, early colonial powers generally respected the territorial and political sovereignty of the indigenous tribes, due to the need to forge local alliances with these tribes against other European colonial powers (i.e. British attempts to check French influence, etc.). However, with the emergence of an independent United States, desire for land and the perceived threat of permanent indigenous political and spatial structures led to violent relocation of many indigenous tribes to the American West, including the notable example of the Cherokee in what is known as the Trail of Tears.