While waiting several hours for the sun to be just right I took several panoramas of Redwall Cavern from the nearest hiking access which is across the river from the cavern. To actually enter the cavern you must use a watercraft of some sort.
While passing the winter, and musing about Redwall Cavern, I discovered that it was possible that the setting sun might shine into the cavern just before it dissappeared behind the cliffs to the west. I didn't figure that out by myself. I had the help of Google Earth, my memory of being in the cavern a year earlier, and a very useful app that provides the sunrise/sunset times for any latitude and longitude. My research told me that the best time to see the sun set into Redwall Cavern was the last two weeks of May and the first week of June. Of course, a similar time separation on the other side of the summer solstice would provide the same view, but there was no way I was going to hike in the heat of late July and early August.
Alas, as the sun dropped below the cliff, I realized the cliff face was too sheer, and the cavern too deep to allow the sun to shine much past the entrance. The white sand reflected some light onto the ceiling, but the narrow band of sun in this panorama is as close as the sun gets to entering the cavern.
Redwall Cavern is one of the highlights of any, and probably all, river trips. Whether the trips are small kayak adventures, big rubber rafts, wooden dories, economic self-guided trips, or more expensive commercial trips, motorized, or not, nearly everyone stops at Redwall Cavern to explore it and pass some time.