Why it looks like this

Kabul is one of the world's highest capitals, set in a bowl of mountains that the city has slowly climbed. The old town and bazaars grew by the river crossing under the Bala Hissar fortress; the 20th century added planned quarters — including Soviet-built microrayon apartment blocks — on the flats.

Decades of war drove huge migration into the city, and much of Kabul is now informal: hillsides covered in mud-brick houses reached by stair-like lanes, their lights at night outlining the mountains above the planned streets below.