In Yellowstone, one of the popular places to stop and look at the scenery is at Tower Falls. Until the spring of 1986, this 132-foot waterfall had a precariously perched boulder on the brink. That year, the boulder fell to the bottom. We visited Yellowstone in the 1970's several times and got pictures of this waterfall with the boulder still there, as you can see below. The boulder to the right of the one that fell is still there. During the 1975 trip, we hiked down to the base of the falls and looked up at the boulder and tried imagining what it would be like to be under this waterfall when that boulder finally came down. The sign at the overlook asked the question about when the boulder would fall, but now it's not there, of course. It also looks like the same trees are there to the left of the creek after 40 years. The trees closer to the overlook have obviously gotten taller.
Tower Falls gets its name from the volcanic pinnacles that line the stream course.
Here are the two pictures side by side for comparison.
Remember, it's not just a picture, it's a story!