The talk reviews the main components of the financial crisis of 2007-09 from a complexity perspective and argues that two decades of ideology driven deregulation, the surge of securitization, the spreading of OTC derivatives and off balance sheet items, excessive leverage, collaterized debt obligations and structured investment vehicles led to the creation of a huge shadow banking system that became opaque and complex to such a degree as to be totally unknowable. Such a system is impossible to regulate. As a result of massive government interventions, partial or complete nationalization, and a series of collapses, the system is in the process of deleveraging, and a large body of new regulation is in the making. The talk will give a sketchy oversight of what is perhaps the most coherent set of proposals for the new regulation, due to the de Larosiere Committee. Finally, the idea of an adaptive regulatory regime will be put forward.