In the past two decades numerous large-scale informal markets have emerged on the fringes of European cities in the wake of global geopolitical transformations. Relying on individualised long-distance connections and adapting to diverse local situations, they produce a proliferating array of unregulated urban architectures while providing habitats for millions of undocumented existences. One such case is the infamous Arizona Market not far from the north Bosnian town of Brko, a place that has been transformed from a border guard post into a major hub for people trafficking and prostitution and now into a multi-ethnic centre of ubiquitous consumption. Another one, Izmailovo Market in the north-east of Moscow, the largest informal trading centre in the region with links to all parts of the Russian Federation and beyond, has grown into a Babylonian site of 15 specialised trading areas that rivals the Moscow Kremlin both in terms of size and visitor attractiveness. And when the 22nd World Congress of Architecture was held in Istanbul under the motto ‘Grand Bazaar of Architectures’, a bazaar of a very different kind traded outside the tourist centres: a vast network of provisional, informal street markets that establish themselves right alongside the building sites of official urban regeneration, beneath terraces of motorways and next to newly constructed tram lines. Before exploring the dynamics of these spaces in more detail, let us address briefly the socio-economic conditions underlying the rise of informal markets.