We study the response of an infinite system of point particles on the real line, initially at rest, to the instantaneous release of energy in a localized region. The blast generates shock fronts that travel sub-ballistically. The density, velocity, and temperature profiles in the growing region between the shock fronts can be obtained from exact self-similar solutions of the Euler equations. We compare these with the results of microscopic simulations. At long times, the results obtained from the simulations show a remarkable agreement with the predictions from Euler hydrodynamics except at the blast core where we show that corrections due to Navier-Stokes terms are important. We will also discuss the "splash" problem where energy is injected from one side of a semi-infinite cold gas.