Why it looks like this

Bao'an is the western wing of Shenzhen, the city that grew faster than any in history. When the special economic zone was created in 1980, this was farmland dotted with villages; today it holds Shenzhen's airport and millions of people.

The map keeps the memory: inside the wide modern grid sit tight knots of narrow lanes — 'urban villages', where the old settlements rebuilt themselves as dense walk-up blocks while the planned city grew around them.