It was a wonderful blue hour, one of the most beautiful I've ever experienced. The light wasn't really blue but rather purple and was diffused by the fog what created some really magical mood.
Frankly speaking it is not really a HDR photo but manual blend. I hardly ever do manual blends because I prefer the look of tone-mapped or fused images but this was a rare case when I couldn't get this image right otherwise than to blend the 5 exposures manually.
You might argue that it's a bit too dark. Maybe, but I like it this way :)
Camera: Canon 50D
Lens: Canon 24-105 f/4 L IS USM
Focal length: 28 mm
Exposure time: 5 s ("middle" exposure)
Number of exposures: 5
E.V. Step: 1 E.V.
Flash used: no
Tripod used: yes
Filters used: no
Software: Magic Lantern 2.3, Photomatix Pro 4.2.5, Lightroom 4.2, Photoshop CS5