Jumping from a rooftop in Eboshigata Hachiman shrine I accidentally jumped on top of one, and immediately a "save symbol" came up in the bottom right corner. Feels like it recorded me doing so, so I thought might miss out on a trophy or something?
I think the type of game would affect what city would be best for post apocalyptic setting. Zombies, virus, alien? Just exploring? Rome, Paris and London are cool, but eg Venice with canals could add an element of trying to avoid dager by swimming.