Grand schemes originally envisioned as the perfect human habitats, many of the world's 'utopian' urban areas ended up as anything but, with some even morphing into hellish dystopias. From the infamous Kowloon Walled City and the crime-ridden Le Vele di Scampia, to Hitler's horrifying Welthauptstadt Germania metropolis, click through the gallery for six of the most notorious failed archetype cities, both projected and realised.