Looks a lot like the woods out behind my parent's place. Every few years I walk through there, the erosion from water flow has it looking quite different each time.
Every now and then, you get some cool under ground flows, you can hear them when they rain, but you won't see anything. When the water level starts to go down, I look around for the exit, then try to trace the entrance. As a kid, some of these were big enough I could crawl into, they opened up into under ground rooms held up by the roots of trees, you could see sunlight in places the dirt was thin.
Dirt piles up, dirt gets washed away, the whole landscape keeps changing whenever I walk back there.
Here's one from a few years ago, a "window' had caved in giving me a shot up to the entrance with enough light to see it. Prior to the cave in, this was about 15 feet long.
