It took a crew of 200 technicians to build a miniature model of a futuristic New York City for "Just Imagine, a motion picture fantasy" released in November, 1930. According to Modern Mechanix, the city of the future was built in an old blimp hangar, and the model covered a ground area of 75x225. Its tallest tower soared 40 feet high. In all, the not-so-tiny model city required more than five tons of plaster to construct. And there's more.
The city contained:
Lofty office buildings 250 stories high, canals carried overhead on suspension cables, airplanes that land on a few square feet of flat space on the side of tall structures, streets with nine lanes and nine levels of traffic . . . Although the model city is futuristic, its construction violates no engineering practices. It is really engineering skill carried a bit farther than today.
And the movie sounds pretty good too:
New York, 1980: airplanes have replaced cars, numbers have replaced names, pills have replaced food, government-arranged marriages have replaced love, and test tube babies have replaced ... well, you get the idea. Scientists revive a man struck by lightning in 1930; he is rechristened "Single O". He is befriended by J-21, who can't marry the girl of his dreams because he isn't "distinguished" enough — until he is chosen for a 4-month expedition to Mars by a renegade scientist. The Mars J-21, his friend, and stowaway Single O visit is full of scantily clad women doing Busby Berkeley-style dance numbers and worshiping a fat middle-aged man. (Jon Reeves, IMDB)
P.S. If miniature cities float your boat, don't miss the Panorama of the City of New York at the Queens Museum of Art. Built for the 1964 World's Fair, the Panorama covers 9,335 square feet and includes "every single building constructed before 1992 in all five boroughs; that is a total of 895,000 individual structures."