Charlie Koolhaas presents some photographs of four global cities at London's Architectural Association.

London vs Guangzhou
One is the super dense city of Guangzhou (formerly Canton) in southeast China, an ancient trading centre that today is China's production hub, producing 80 percent of the world's clothes and furniture, and inhabitated by traders from all over the globe. This city is contrasted with the disused (and about to be re-used) parts of East London, which exemplify the stagnation facing many historic cities. This area of London is depopulated – many of the buildings are so old that they are uninhabitable – and is being forced to conceptualise its rebirth and reinvention in the midst of a grim economic climate.

Lagos vs Dubai
Dubai is a powerful financial centre that attracts huge international investment: it is also one of the most multi-cultural cities in the world, with an estimated 80 percent of its population expatriates from across the globe. Subjected to intense media scrutiny in the wake of the global economic crisis, it has become something of a symbol for the world's spending habits. Lagos is one of Africa's most influential historical cities, containing many examples of both the chaos left over from Nigeria's colonial past and its feverous responsibility as a production and financial "hub" for the rest of Africa and exporter of resources to the rest of the world. Both Dubai and Lagos are important centres of power outside of the western world and are distinguished by their relative tolerance and stability within their respective continents. Beatrice Galilee