NASA's dizzying concept art imagines ribbons of farmland in space

Back in the 1970s, NASA was creating seriously trippy images of lush, green human habitats crammed inside tubes in space. Farms and happy townsfolk stretch upwards and even wrap over your head, like an M.C. Escher vista. More weirdness below. » 8/30/10 11:30am 8/30/10 11:30am