Yahoo Homes just published a slideshow by French artist Martin Vaissie, 25, showing abandoned castles in France and Belgium. Two of the castles he visited, Chateau Rouge (aka the Red Castle or Red Hotel, aka Chateau Bambi) and Chateau de Noisy (aka Noisy Castle, aka Chateau Miranda), are especially popular among urban explorers. We found videos of them on YouTube, if you'd care to explore them yourself.
Chateau de Noisy:
Also on Yahoo Homes: