This is going to be a very unusual post. It's about 95% irrelevant to the Haunted Mansion, and yet, in order to claim that 5% it's necessary to wade through the whole. Not that the topic is dull, because it's not, so we'll have some fun getting to that 5%.
One of the things we admire about the HM is the sheer audacity in its imagineering. Those stretchrooms, for example, are just as impressive today as they were when they were first designed, nearly a half-century ago. It took a bold imagination to dream up something that unique. Since they were in the building when it was built (in 1962), they were designed during the period when Rolly Crump and Yale Gracey had the Mansion assignment. In fact, Rolly designed the original stretchroom portraits, but Marc Davis didn't like them and came up with a set of new ones (and don't we all wish we could have seen Rolly's versions!). The ingenious stretching effects, with a complex system of telescoping wall panels and unrolling paintings, were almost certainly a Yale Gracey invention.
For sheer scale, however, the prize for audacity goes to the Grand Ballroom, the largest "Pepper's Ghost" illusion ever created. The arcade that you look through is roughly 90 feet long and 30 feet high. There are eight panes of glass, each one about 10.5' x 23.5'.
Believe it or not, in February of 1942 Japanese submarines appeared along the California coast, and one of them actually fired a few shells at an oil storage facility in Santa Barbara. One of them hit a pier. That was a rude wake-up call. Suddenly it was apparent that the continental U.S. was vulnerable to attack. Among the prime targets for possible Japanese bombing runs were a number of important aircraft manufacturing plants along the west coast. It was decided that these plants had to be disguised. For help, the military turned to the major movie studios—MGM, Fox, Warners, Paramount, Universal, and of course, Disney. An army of set designers, art directors, painters, animators, carpenters, and prop designers took up the task of camouflaging the airplane factories and other vulnerable targets, 34 in all.
The Boeing manufacturing plant in Seattle was not the first to get the magic transformation, but frankly it provides some of the best photos, so we'll start there. The site covered nearly 26 acres. What the movie men did was design an entire fake neighborhood, a Potemkin Village, all of it set on a vast field of chicken wire and burlap and elevated above the plant on wooden stilts. [I'm told that the following photo and the one below it are not the same site, as there were two Boeing plants in the vicinity. See the Comments. Nevertheless, you can still get a rough idea of the before-and-after effect by comparing them.]