Before revision: Trade and economics 250x250px|alt=A map depicting the Silk Road and relevant trade routes |Long-distance spice trade routes along the Silk Road (green) and other routes (red) Trade, the voluntary exchange of goods and services, has long been an aspect of human societies, and it is seen as a characteristic that differentiates humans from other animals.
After revision: circa 1st century ADTrade and economics 250x250px|alt=A map depicting the Silk Road and relevant trade routes |Long-distance spice trade routes along the Silk Road (green) and other routes (red) Trade, the voluntary exchange of goods and services, has long been an aspect of human societies, and it is seen as a characteristic that differentiates humans from other animals.