The HOLE with no bottom - The bottomless pit.

I discovered this hole in my back yard a few months ago. After a while, I decided to test the depthness just out of curiousity. I took the water hose and poured water into the the hole for about five minutes, and the hole never filled. I looked around nearby for a possible exit, but never found one. Therefore, my only conclusion is that the hole is extremely deep. I wonder whether it was dug by a chipmunk or what type wiseguy creature!!

I'm baffled. My grandson, also, tried filling the hole. No luck.  Therefore, it has been deemed "the hole with no bottom".