 This white feature here is called the wall of windows. It's actually limestone and started out with a little tiny hole, like the hole on the left, and then it's eroding and eroding and eroding. You've got the bridge on top and then the bridge on top will fall away and then you'll have the two hoods left standing. The difference between a natural bridge and an arch? Natural bridges are formed by streams and rivers running through underneath, cutting away. Where is this bridge? This is actually frost wedging. Okay. Where it freezes and thaws and freezes and thaws and freezes and thaws and then it breaks away in a different layer.