With the success of the Apollo missions, NASA turned its eye to the prospect of offworld colonies. The space agency ran its “summer studies” at NASA Ames in 1975, allowing experts and artists to share their visions of what space-based colonies might look like. The resulting concepts were bold, including space habitats in which 10,000 people would “work, raise families, and live out normal human lives,” according to one of several NASA studies. The wheel-like habitats would simulate gravity, allowing for traditional homes, monorails, trees, grass, bodies of water, and agriculture. There was hope that some habitats might appear as early as the 1990s, but these ideas, though wonderful, were a bit much from a technological perspective.
Source : https://gizmodo.com/7-space-concepts-that-were-too-wild-for-nasa-1848623134