This Glitch Requires use of the Item Jumping Glitch, so practice beforehand!
Get to the point in the chapter "We Dont Go to Ravenholm..." where Grigori Throws you the shotgun. Item Jump onto his catwalk, and your done! Use that item to climb along the many catwalks and rooftops of ravenholm. This can be done elsewhere, but there is alot less area to explore. Have Fun!
This Glitch was Found by ArmoredScout