Caerphilly Castle - the largest castle in Wales at night.
After looking around the castle during the day, I drove to back from Cardiff to Caerphilly in the evening (around 9PM). I expected to see the castle nicely lit at night, like most famous buildings in other places. But instead it was completely dark. I had to use longest possible exposure.

Camera settings: manual mode, ISO400, lens zoomed to 22 mm, mirror lockup and self timer. I would prefer lower ISO and longer exposure (maybe 60-90 seconds), but 30 sec is the longest exposure I can get without remote release device.
Converted from raw with color temperature set to 6350K.