Secret cave

There's an old tree that fell down years ago, when I was a child. I played there for some years. On visiting my parents my son has now found this tree, but it's very different, having sunk in to the ground! It has cracks all over, and is covered in flora and fauna - including lizards! completely fascinated by them, he watched them for some time. I found this crack with some kind of lichen growing. My husband has a shot with a lizard head poking out, not sure if Blip would let me upload that ;)