Frank Lloyd Wright
1935
No one can say that this building isn't an architectural wonder. It is a perfect harmony between nature and man-made structures. Then again, its built over a waterfall...its kind of an instant-win. What I find interesting is that Kaufmann doubted Wright's experience working with reinforced concrete so much so that he put together a report and sent it to a third party to confirm that everything checked out. Wright took offence and threw a hissy-fit and threatened to withdraw from the whole project. Kaufmann ultimately folded to Wright.
Also, it has been stated that the contractor on the project produced different construction plans and argued to increase the reinforcing steel in the floor slab. Wright of course refused the suggestion, but the contractor quietly doubled it anyway. Luckily, because in recent years it has been found that even doubling it was not enough. The building has since been prone to mold infestation, leaks, cantilever deflections and various other structurally deficiencies. It was actually nicknamed "Rising Mildew" as condensation under roofing membranes was also an issue, due to the lack of damp proofing or thermal breaks.
I was always taught to design something that can be constructed in a safe and uncostly manner. This design took 4 years to complete and at every step of the way engineers, contractors and the client told Wright that the concrete loads and steel reinforcing was not enough and still he refused to accept that. His own ego clouded hes judgement and turned a families dream-house into hes own footprint.