Having lived in Tokyo for years, the elephant in the room is "cars". The whole city is full of pleasant mixed use neighborhoods that are more or less car-free, and centered around public transport hubs that have everything you need around them. People, including unaccompanied children, can and do safely walk and ride bikes everywhere at all hours of the day, including when grocery shopping etc. The world can learn a lot from this.
Before anyone chimes in saying "nO tHeRe r cUrS iN tOkYo tOo" - of course there are! The point is the city isn't designed around cars. (and the parts that are are the least pleasant)
Before anyone chimes in saying "nO tHeRe r cUrS iN tOkYo tOo" - of course there are! The point is the city isn't designed around cars. (and the parts that are are the least pleasant)