According to The Atlantic, it took map artist Gareth Wood, aka Fuller, 10 years to produce this psychogeographic map of London, soon to be on display at the Royal College of Art. Excerpt above. Fuller below.
Mordor, recreated in the style of Google Maps. See the comments on this Geekologie post for the best imaginary-map suggestion yet. Fortunately, Geekologie also links to a real interactive map of Middle Earth.