PLC, DCS, OPC, SCADA, Modbus, Stuxnet, we all hear about these terms quite often nowadays. But what are they? Why did Stuxnet target a PLC and why it is so "critical"? How can an attack on a PLC affect our daily businesses or our home computers? And how are all the Critical Infrastructures interconnected: Telecom, Electricity, Gas, Water, Banks, Transportation? This is not just another Critical Infrastructures presentation. This presentation will take the global picture approach and show you why you should be worried. We will also emphasize on the local context (Luxembourg, France and Belgium) and try to answer this question: is the fact that Luxembourg is nuclear free mean there is no risk?