Wharncliffe Viaduct, Hanwell, built in 1836-37 to carry the Great West Railway over the Brent River Valley (Not a big valley!). Designed by Isambard Kingdom Brunel. It is now a grade 1 listed building.
I cycle this way a lot. I love the views around the viaduct, from both sides.
The other side. Church Fields/ Brent Lodge park (popularly known as the Bunny Park, as there is a small zoo there). Shot into the sun.