Ca Clunk

I was in a parking lot one day, and was getting ready to leave and I made a right turn, not to sharp, and heard this big clunk noise. I looked back, and didn't notice anything that I could've run over. Then, I stopped the car, turned it off, and looked under where the exhaust is, and didn't see anything. I just did a quick look didn't see anything. It definitely sounded like it came from the rear of the car.
Can you all shed some light on this for me as to what it might be.

Thanks