When I was in my early 20s, my family took a trip to Yellowstone National Park. One afternoon, we saw the Lower Falls of the Yellowstone River, the largest waterfall in the Rockies, twice as high as Niagara Falls. As we walked out to the main overlook—a steel platform girded with four-foot rails and crowded with camera-toting tourists—I saw another overlook that seemed to have a better view. The trouble was, this second overlook was blocked by a fence with signs warning, “Extreme Danger.
