Answer:
Europe´s entire political, economic and social life changed with the discovery of the Americas in the 15th century, and soon after, by the discovery by the Portuguese of a way to reach Asia without having to cross through the barricades established by the Arabs on the continents´ mainland. These two discoveries, and the encounter with the rest of the African continent, not just the northern portions, opened up, in the 15th century, and up until the 20th century, completely new frontiers and established Europe as the leading power at the time, especially those nations who gained colonies.
After these discoveries were carried out, and as European power began to expand their control over the American, African, and Asian colonies, Europe´s power, and hunger for it, increased. It also caused a terrible power struggle among the different European countries for who had the most territories and colonies, as well as wealth. Thus, war and conflict between these powers was also a direct result of the changes that began to take place from the 15th century till almost the 20th century.
But this greed for power, gold that came from the Americas, control over trading, and almost everything else that came from colonization, did not just affect the rulers of European countries; it also affected the everyday citizen, with some becoming so greedy that they would leave everything else in the desire to acquire a portion of the riches from the colonies. Trading grew and increased enormously and the growth of rich people, and also the division between the rich and poor in Europe, grew dramatically.
What caused this sudden change, from a small continent, to such an important and powerful one? The need to re-establish trading with India and the Far East, which was cut off by the blockades created by the Arabs against the Christian world. This was the main reason why Europeans ended up going out, despite all, to discover new lands.
