Leaving aside issues of cost, logistical viability and politics, where ahold they hold an Olympics?
It occurred to me toda that London is pretty clearly a hugely important city, a world centre, and so an appropriate place to hold an Olympics. In retrospect, the choice of Atlanta in 1996 seems, b comparison, really bizarre. Atlanta isn’t even the fifth greatest city in its own country.
So we know the next Summer Games are in Rio. Given importance however you want t define it - current size, power, economic might, cultural impact, historical value, n whatever mix you like, plus considering the need to move the Games around globally a bit - and eliminating any city that has ever held the Olympics before, where should they hold the 2020 Games, assuming no cost or logistical burden? Heck, go out several Olympiads if you like.
Btw, in case you don’t have a list handy, the cities that have hosted the Summer Games: Athens, Paris, St. Louis, London, Stockholm , Berlin, Antwerp, Amsterdam, Los Angeles, Melbourne, Helsinki, Tokyo, Rome, Mexico City, Munich, Montreal, Moscow, Seoul, Barcelona, Atlanta, Sydney, and Beijing. You cannot use any of them.