Noctilucent Clouds over the River Clyde.
I took this photo a few years ago while driving home one night. Typically I had no tripod with me so I had to try to take a sharp 5 second exposure while holding the camera on a railing! I failed miserably but I still quite like it!
Noctilucent clouds are the highest clouds to form in the atmosphere at altitudes of 50 miles or more. A relatively rare sight, these silvery filaments are illuminated by the sun from below the horizon. Nobody really knows how they form and they appear to be a relatively recent phenomenon which leads many to believe they may be linked with climate change.