Why was long distance trade in exotic goods such an important phenomenon in north america, europe, and africa?

The long distance trade led to development of urban centers in the areas where merchants used to meet and trade which led to growth of different areas. This was the genesis of the civilization as many communities interacted together. This cultural exchanges such as intermarriages led to the growth of new society and in some countries it marked the begin of new language that enabled people to understand each other and share ideas together.