An old gristmill sits beside a placid millpond, its water wheel rotating at a stately pace. It's an iconic image of simplicity and serenity. But in their day, mills were complex, high-tech, noisy machines. And although the mill itself was stationary, gristmills were responsible not only for traffic, but for the very roads down which that traffic traveled – then and now. Colonial mills created many of the roads we still drive on today.