I suggest two different though related challenges ( that could be merged into one, but I would prefer two different ones).

Create your own utopia: you are to map your perfect nation, the city of your dreams, the castle where you would happily live. The perfect, lovely, place, a dream who has come true.

Create your own dystopia: from a nazi dominated world to a concentration camp, from the laboratory of an evil scientist to a slum, super polluted city where your life is simply hellish, you are to map the place where you won’t be even for few minutes, no matter what.