The "European Blackout" of 4 November 2006 is a key reference in current debates on transnational electricity infrastructure vulnerability and governance. Several commentators have observed that to understand what happened, one must look at history. Our paper answers this call and demonstrates how historical choices, path dependencies, and ways of dealing with these afterwards, have shaped Europe's electric power infrastructure and its vulnerability geography. We show that the decentralized organization of transnational electricity infrastructure and governance, often blamed for present-day power grid fragility, was informed by reliability considerations that still count today. We also address the (meso)regional logic of the failure, foregrounding how stakeholders from different parts of Europe historically chose to collaborate in different ways, with due consequences for the 2006 disturbance and other recent blackouts. Finally, the paper observes that today's notion of transnational electricity infrastructure vulnerability, supposedly demonstrated by the 2006 blackout, is highly contested as many stakeholders find the system extremely reliable.