Back in the days of the Roman Empire, the cost of shipping a cargo across the length of the Mediterranean Sea–more than 2,000 miles–was less than the cost of carting that same cargo 75 miles inland. This meant that people living on the coast had a vastly larger universe of economic and cultural interactions with other people available to them. A geographic treatise pointed out that, in ancient times, the European hinterland was "lingering in a backward civilization as compared with the Mediterranean coastland." As late as the middle of the nineteenth century, San Francisco could be reached both faster and cheaper by water, across the Pacific Ocean from a port in China, than by land from the center of the United States.

Thomas Sowell

Discrimination and Disparities