It's time to build: a New World's Fair
The last really prophetic world's fair was New York, 1939. That's famous for GM's vision of the future of 1960, the original "Futurerama" . Freeways everywhere.  RCA had television. AT&T let you make free long distance calls. All that stuff happened.The 1964 World's Fair had another GM exhibit. Colonization of the Moon. Underwater cities. None of that happened.What could we have in a World's Fair now that looks ahead? Colonization of Mars? Mars sucks as real estate. There may be research bases there someday, but as a self-sufficient area, it would be tougher than Antarctica or a continental shelf. Robots may some day be a thing, but they still don't work well in unstructured environments.