In the lead up to the global financial crisis, there was a substantial credit boom in advanced economies. In the Eurozone, cross-border flows played an especially important role in the boom-bust cycle. This column examines how the common currency and linkages between member states contributed to the Eurozone crisis. A very strong relationship between pre-crisis levels of external imbalances and macroeconomic performance since 2008 is observed. The findings point to the importance of delinking banks and sovereigns, and the need for macro-financial policies that manage the risks associated with excessive international debt flows.