The first important motivation was economic. Explorers searched for the "fabled riches of the east"; the motivation of Christopher Columbus, for example, was to find a sailing route to China that would be faster and more profitable than the overland "silk road." Europeans saw the Americas as sources of valuable raw materials such as gold and furs, while the Orient provided spices, tea, and silk. As is true of globalization today, Africa and the Americas were seen as places with cheap labor for raising cotton, tobacco, sugar, and other crops and mining metals. A typical example of this was the "triangular trade" in which the English shipped manufactured goods to Africa, traded them for slaves, brought the slaves to the Caribbean, and brought back molasses to England.
Another important factor was European political rivalries. No European country wanted its enemies or rivals in Europe to control the wealth and vast territories arising from colonialism, and thus, for example, the French, English, and Spanish vied to control territories in North America.
Finally, Christianity was a missionary religion, with many Christians feeling they had a duty to convert non-Christians. Jesuit and Evangelical Protestant missionaries were especially dedicated to reaching people in areas remote from European influence.
There are generally said to be three main factors that motivated Europeans to explore and colonize the New World. These are given as “God, gold, and glory.” Of these, the last two are typically believed to have been the more important.
Europeans wanted to explore and colonize for “gold.” That is, they wanted to get rich by finding new lands and exploiting their resources. Individuals wanted to get rich and so did the countries that sent the individuals out to explore.
Europeans also wanted glory. They wanted to be personally famous and to be given titles that would make them part of the elite of their society. Countries also wanted glory. They wanted the prestige of having large empires.
The desire to bring Christianity (“God”) also played a role in this process. However, historians generally agree that the more worldly motivations played a greater role.