The Nightmare Stacks map
I very much enjoyed "The Nightmare Stacks" by Charles Stross, my favourite book of the "Laundry Files" series (as released so far).
The plot being placed in a real place, I used the excellent umap website to draw the places & campaign movements named in the book as an openstreetmap overlay (actually 3 layers: places & leylines from the preparation phase, second the campaign of the Host of Air and Darkness, third the counter-movements by the Urük):