Metabolists’ urban designs, which often proposed sea and sky as the site for human habitats of the future, appear wholly impracticable at first glance. However, they were not simply illusive fantasies that architectural historians tended to portray. Just like modernist precursors Bruno Taut and Le Corbusier who believed architecture was the foundation for social change, Tange and his disciples were inspired by the prospect that a revolution of architecture and a radical reconstruction of the city, more than anything else, could lead to a new order for modern society.1 Their proposals followed a long tradition of utopian planning, but their unique interpretation of modern technology added fresh ideas to this tradition.