Most of these are from construction projects from other countries, but a few were gathered from home inspectors here in the United States (i.e. plastic water bottle stopper in pipe, tree growing through rooftop). There's plenty more over at Dark Roasted Blend's Unbelievable Blunders in Architecture and Construction series and This Old House's Home Inspection Nightmares to marvel at.
The last image in the slideshow is an argument of why NOT to hire a professional.
Have any particular home improvement nightmare stories or photos of your own. Send them to us!