The Crofton pump house and chimney were built in 1807 and started working in 1809. I think the patches on the wall were where the beams for the 1812 Boulton and Watt pump were passed through the wall.
I thought I'd post a photo I took of the beams of the Crofton Beam Engines. These are the oldest working steam engines in the world!
Today's photo is of a Tower Bridge Steam Engine. One of two identical engines, it is housed under the south approach to the bridge.
Today's photo shows 925 years of construction in just one frame.
Being lazy, here's a vertical interpretation of the view to the north-west from Tower Bridge.
Continuing with my series of images of London, here's a view North West from Tower Bridge. Like the photo of to the west, this was taken from the west walkway and has been processed through Photomatix.