In this seminar I will discuss informally the future of computational simulations. I speculate a coming era propelled by real-time, cloud-based, high-fidelity simulation and design of complex, multi-disciplinary, multi-scale systems. I envision ubiquitous access to these Big Simulations through virtual and embedded reality, not unlike how we access big data today through web search. These simulations should complement and enhance the creative human mind. They have the potential to revolutionize how hard technology, e.g., that of airplanes and rockets, is developed. Based on first-principle physics instead of on data, these simulations can enable innovators to quickly, cheaply, and safely explore designs that function differently from what have been previously tested. Today’s risky, billion-dollar, multi-year research and demonstration projects, like designing and flying a new hypersonic vehicle, can turn into tomorrow’s undergraduate project. I will discuss how the research topics of ACDL are contributing to the future of Big Simulation.