The US now has training camps featuring imitation "Arab” urban districts, and has picked up the Israeli practice of entering a dense neighbourhood not via the street, but by crossing through homes – a parallel pathway to the street, running from one interior room to another by carving holes in contiguous walls, and dealing with the inhabitants as they come across them. They have learned, above all, that the city itself has become an obstacle. And while it is true that they can simply bomb a city to pieces – as we've seen with the bombing of Aleppo and other cities by Syria's government and its allies – we have not recently seen the total destruction of the Hiroshima nuclear attack or the fire-bombing of Dresden.