About three-fourths of the way down the trail to get to the entrance of Crystal Cave in Sequoia National Park (CA) you will come to the Cascade River and Cascade Falls. The Cascade River runs just outside Crystal Cave (not through it — Yucca Creek runs through Crystal Cave and empties into the Cascade River) and has a number of short falls that can be seen as you descend down the path which offer wonderful photo opportunities.
The hike down the Crystal Cave trail to the cave entrance takes about 10 – 15 minutes, but you may want to add more time in so that you can spend some time taking photos along the way without being rushed.