Tokyo, Japan

Tokyo is the city other megacities try to be. 35 million people, no graffiti, trains to the second, a different micro-neighbourhood every five blocks. It is at once intensely urban and weirdly intimate — Shimokitazawa feels like a town, Shibuya like a planet, and they are a five-minute train apart.

For newcomers the early months are about decoding subtle social rules and learning enough Japanese to order at a non-tourist izakaya. The reward is access to a culture that runs deeper than any sticker version of itself, with weekend hikes a 90-minute train away and convenience stores stocked with food better than many countries' restaurants.

Good for: detail-lovers, food obsessives, anyone who values civility highly enough to put up with the language curve.