Oh, believe me, I know! There is plastic edging that goes 6 inches down from the base of the fence, it is just covered by the dirt. On the other side of the fence is a downward slope covered in heavy landscape fabric and rock. So even if he made some sort of monster tunnel, he would hit a roadblock. I have been watching closely and all escape attempts (and there have been many in the last 48 hrs) have been thwarted.Very pretty enclosure!! Can the tortoise dig under the wooden fence in the back and get out? Is your tortoise a Russian? If so, they can really dig to escape. They are real escape artists.