A project called Britain From Above aims to put 95,000 historic aerial images of Britain online.
The first 10,000 images are already available.
The project uses images from the Aerofilms collection, which it describes as follows:
Dating from 1919 to 2006, the total collection presents an unparalleled picture of the changing face of Britain in the 20th century. It includes the largest and most significant number of air photographs of Britain taken before 1939. The collection is varied and includes urban, suburban, rural, coastal and industrial scenes, providing important evidence for understanding and managing the built and natural environments.
I can see I'll be spending a lot of time browsing through those images. They take us back to a bygone era that's largely ignored today.