Slide 1 of 28: We all know that self-build and renovation projects come with plenty of obstacles, but for some unlucky homeowners, unforeseen circumstances can lead to major construction disasters. Located around the world, these bold buildings all faced their fair share of difficulties. From the Georgian townhouse that dramatically collapsed, to a 24,000-square-foot mansion that remains unfinished despite four decades of work, these might just be the world's most challenging home projects.