Zion National Park has a variety of worthwhile destinations/activities. One unique one is a hike through the Narrows, a 16 mile hike, 60% of which is in the Virgin River with walls soaring on both sides.
We walk along the river with vegetation supported by the river, including "weeping walls", many deer, all on a paved trail that undulates a little but otherwise is flat.
We reach the mouth of the Narrows as some people emerge from it. There is always the option of going in a mile to get a feel for it and then turn around. Or, a local company will rent you a bike and equipment and you ride to the mouth, change and plunge in for awhile. We chose to reach this point and turn around, ha, ha. That was always our intent. Would be a neat experience but walking in cold water is not on my list of priorities. Instead we....
….turn around and enjoy some light activity as we prepare for something more. Outside the visitor center, there is a neat model that shows the geographic features, including #10 which is Angel's Landing and then that prominent plateau to the left is Observation Point, a destination in a day or two.