"Economic geographers and geographical economists have been using different methods in order to analyse the location of economic activity. These different approaches to the same topic have, paradoxically, resulted in very similar geographical configurations: a ‘spiky’ world dominated by large metropoli, where intermediate and peripheral locations tend to matter less and less. This apparent similarity in outcomes hides, however, different explanations and policy recommendations. On the explanation side, economists have focused on understanding how the interaction of economic agents in reduced geographical spaces gives rise to large urban agglomerations. Geographers, in contrast, have increasingly concentrated on relative conceptions of space which highlight the importance of the interaction among often far-away places. On the policy side, economists have favoured spatially-blind policies, while geographers are strong advocates of place-based policies.This interdisciplinary proposal will aim at bridging the gap between these two contrasting approaches, by combining concepts and methods developed by economic geographers and geographical economists in order to better understand how economic agglomeration emerges and how the interaction among distant agglomerations contributes to reinforce, rather than weaken, their importance. It will also elaborate on the adequate policy-mix which could be applied in order to optimize policy intervention in diverse geographical context and time settings.In addition to bridging approaches, the proposal will advance knowledge at the frontier of both disciplines with a combination of theoretical and empirical papers revolving around three key sets of questions where new research is particularly needed:1. Origins and microeconomic dynamics of spatial spikes2. Territorial dynamics and interactions among and beyond spatial spikes3. Spatial policy design"