The collapse spread through financial disruption, falling activity and unemployment. Banking failures and monetary contraction are central to many explanations, alongside international constraints and policy choices. Power question: who could preserve access to payments and credit, and whose livelihoods depended on those decisions? Avoidance question: could earlier protection of payment functions, different bank-loss arrangements or different monetary responses have reduced the contraction? Lab proposal: compare interventions under bank runs and collapsing demand; measure employment, output, concentration and distributional costs. Do not equate a modelled recovery with a definitive reconstruction of history.