No clear evidence has been found to show how the earliest human beings traveled. Archaeologists date the earliest evidence of any kind of travel from the end of the “Ice Age,” about 40,000 years ago. Evidence suggests that some kind of trading occurred in prehistoric times, since many raw materials, including “luxury” items like amber, have been found far from their likely sources. After the last glaciers of the Ice Age melted (around 12,000 years ago), people began to grow crops and raise livestock. The steady supply of food produced by farming created the conditions for people to live in towns and cities. From these early times to today, trade and travel encouraged each other to grow and expand.