Why it looks like this

Busan has almost no flat land: steep hills drop straight to the sea, so the city grew as strips — along the harbour, up the valleys, around each beach — connected by tunnels and bridges. Districts feel like separate towns because the mountains between them were never built over.

During the Korean War, Busan was the temporary capital and the one major city never captured; refugees multiplied its population, building hillside neighbourhoods whose steep stepped lanes still climb above the port.