There's an area in Archdragon Peak in DS3 around the middle part on the back side of the wall where the Nameless King is if you go down to the lowest platform you can see some scaffolding that wraps around the bridge pillar and it looks totally stable and as if you were meant to find and explore it.

The scaffolding has no physics. It's just a phantom and you will fall right the fuck through it. 😖