The Green Book was a travel guide for black Americans who wanted to travel–or had to travel for personal or family reasons. It was a guide to lodging places where they could stay—“were allowed”—to stay.

I didn’t learn about The Green Book until a few years ago, but one day as a child, I learned why it was necessary. It was perhaps the beginning of my education about racism.

My family was white. We liked to take trips. At that time, a family could afford modest trips—for us a day’s journey into the Smoky Mountains, for example—at a cost that didn’t break the bank. We stayed in inexpensive cabins and ate picnic lunches to avoid a lot of eating out.

One day we stopped at a gas station. A black family had experienced car trouble. They stood to one side, out of the way, while their car was worked on. No nearby motels or restaurants for them if the car took a while to fix.

I began to notice signs. No Coloreds and Whites Only.

I realized people without white skin couldn’t stay where we stayed. They couldn’t eat where we ate.

Black cooks worked in kitchens of restaurants where only whites were allowed to eat. It seemed so unfair. And it was.

That was only a modest dent in my understanding of white privilege. It didn’t speak to larger issues of voting and jobs and schools. But that day was when I first realized the restrictions on a simple family outing if you weren’t the right color.