International trade represents the sale and trade of goods, services and capital across international borders. Such trade of food, clothes, machinery, oil, commodities and currency gives corporations access to customers throughout the world, and it gives customers opportunities to purchase a wider selection of goods and services. International trade can be traced back centuries, even to the ancient network of trade routes that comprised the Silk Road that connected Asian markets to the Mediterranean Sea more than 2,000 years ago. While international trade is more expensive than domestic trade, the profits that can be generated by attracting customers in foreign markets is highly desirable and often worth the risk of increased transportation and distribution costs. Products sold to the global market through international trade are known as exports, while products purchased and brought into a country through international trade are considered imports. International trade can be complicated through the use of tariffs that are sometimes assessed by countries to increase the price of imports to make them less attractive to customers in that country. Trade restrictions can also be imposed by a government or the international community against a nation that is engaging in unsavory activities, such as supporting terrorism, human trafficking or conducting research on weapons of mass destruction. Thus, international trade is often a political tool as well as an economic indication of a country’s global presence.