Contributor(s): Professor Paul Kennedy | All great empires have required a sophisticated logistical system, and a secure communications system to sustain themselves. In a world of endless challenges imperial ambitions soon collapse. This lecture will examine the hard, infrastructural underpinnings of the Roman, Spanish and British Empires, and reflect on how the USA compares in this regard.Paul Kennedy is J Richardson Dilworth Professor of History at Yale University and Philippe Roman Chair in History and International Affairs at LSE.