Latin American cities are typically based around a central square flanked by a cathedral, city hall and other municipal buildings.

Not El Alto. La Ceja, the centre of Bolivia's third-largest city, is a grimy, bustling commercial district of pot-holed roads, belching minibuses, street vendors and packs of stray dogs. The air - thin and cold at 4,100m (13,450ft) above sea level - smells of poverty: a mixture of unwashed clothes, rotting vegetables and urine.