During the time of exploration countries were competing for new land and bigger territories. The main countries that were leading in this race were Britain, Spain, Portugal, and France. These nations were already the most powerful nations in the world but then it became a power struggle over each other. Power was the most important reason for exploration but gold was also a major contributor.
When Spain first went over seas, with Christopher Columbus leading the way, they discovered that the Myans were rich in gold and had no clue of their fortune. When word got back to the other nations that a lot of gold was found they jumped on the opportunity to explore the upper lands above South America. This is when Britain came across North America where they thought was going to be rich of gold was actually only soil and rocks. They took over the land from the Native Americans and used their land for power.
When people started to migrate to the new areas of land colonies than formed. This made the economy of the founding nations boom. The British, used their new land to their advantage and used the colonies for industry and exporting/importing goods.