Big Humpty takes the River Medlock through a short but large egg shaped culvert.

A large storage tank in Bolton that outfalls to the Croal, unlike it's sibling across town this one has a large central column.

A 300m long storage tunnel that slows flow from an incoming sewer before it enters Bolton's outfall sewer, the bottom end was a filthy mess.

A connecting tunnel/overflow for Manchester's massive outfall sewers.

The River Croal flows through and under Bolton town centre in a series of culverts. They are constructed mainly from stone and concrete and are quite large further upstream.

Found below the streets of South London this Victorian beauty is officially known as the Clapham Storm Relief

This storm relief varies from 6 to 16ft and collects overflows from multiple sewers including the Effa, Balham and Southern High Level sewers.