One of my favorite non-fiction books is The Third Wave by Alvin Toffler (referral link). He points to several truly revolutionary points in human history: the transition from hunter-gatherers to agricultural society, from agricultural to industrial, and industrial to digital. The first transition occurred in the mists of pre-history, but the transition to an industrial society occurred only a few centuries ago.
And one of the most important aspects of the industrial revolution was the mechanization of farm work, which allowed farms to feed more people. Starvation was relatively common before the industrial revolution, which effectively wiped it out in developed nations.
Cyrus McCormick was one of the men responsible for that. He invented a mechanical reaping machine--the Virginia Reaper, as it was commonly called. With it, 2 men and a horse or mule could harvest as much as 5 men working individually, with less waste. It then inspired other inventors to develop their own innovations which meant more food safety for all.
And it all started on this farm, where the existing buildings have been preserved and rebuilt to their nineteenth century state. Inside the mill sits two millstones and all the wooden gears and mechanisms to grind wheat into flour. Another building serves as a museum devoted to McCormick's farm machine business, while the farm house shows you what life was like for a middle class farming family in that period. There’s even a short trail to the nearby mill pond. It's all in great condition, and an amazing little piece of history. And it's free!
Cost: Free
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