Me and Bungle were in Manchester one evening and decided to take a look at the culverted stretch of the River Irk known as 'Optimus Prime'. The culvert is short in length however compensates by its width and height - easily 20ft wide if not wider and at some parts even greater in height, its mostly Victorian brick however does have a few minor modern additions.
Besides the usual culvert features of pipes running into it, discarded items of various eras and shape/material changes it also has a small bridge cutting through it at its highest point, believed to carry cattle many years ago.