The transcontinental railroad

Before 1869 the journey from the east coast to California took half a year, either by wagon across the plains or by ship around South America. The railway created the need for standard time zones, adopted in the United States in 1883 — before that every town kept its own solar time and timetables were practically unreadable. It also made commercial bison hunting viable and carried the hides east. Chinese workers were paid less than white ones, were left out of the famous photograph at the joining, and thirteen years later met a law barring their entry.