URL：https://images.theconversation.com/files/149853/original/image-20161213-1596-wf9uvd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=333&fit=crop&dpr=3
掲載元：https://theconversation.com/these-six-utopian-cities-of-the-future-will-help-you-re-imagine-life-on-earth-70280
