Recently I came across one of the best tools I’ve ever found online, and it’s completely free! The National Library of Scotland has taken modern satellite images and placed old maps over the top.
You can select your map (our favourite one is the OS Six Inch 1888-1913), select your area (the whole of Wales is covered) and start browsing the map. The truly brilliant feature however is the little slider called “Change transparency of overlay”. As you move this slider, the map begins to fade, and you can see the satellite image below. It’s such a simple way of seeing the changes in your area, and of spotting historical features that still survive in amongst the features of the modern world.
Click here to take a look. (Although, I do hope you weren’t planning on doing any work right now because this tool is going to take over the next few hours of your life!)