Why it looks like this

Ahmedabad's walled city, founded by Ahmad Shah in 1411, is made of pols: small gated neighbourhoods of a few dozen to a few hundred families, entered through a single gate, full of dead ends and hidden courtyards. The maze had a purpose — it was a defence system in street form, and a social one too, with each pol housing one community.

Across the Sabarmati river, the west side tells the opposite story: planned modern districts, university campuses and wide roads. One river, two ways of building a city — which is why India's first UNESCO World Heritage City makes such a special puzzle.