We were on a camping trip, just registering, and I was taking a picture of a bug on the front window. The ranger said, "If you like taking pictures of things, come see this" and brought me round to the side of the guard shack.
This is a moth, not a leaf! Amazing enough on its own. How can it fly with those crumpled-up wings? But now look at this view from the side:
That was my marvel for the day.