Taken right next to the Hellmouth pit. In the building used as a ramp there is a texture missing for the inside of the building allowing a view of the outside however, upon viewing from the outside the texture is there resulting in what looks like a one way mirror. Not game breaking just a visual glitch.
https://imgur.com/M6SRqw2
https://imgur.com/hhqfEcb
Texture in question