The website presents 21 animated illustrations that explain the inner workings of a variety of steam, Stirling, and internal combustion engines. For the sake of a better observation, the speed of animations can be varied by means of a simple control panel. The website carefully explains each step of the portrayed engines. The animations, though simplified, reflect even small details of the real engines, such as differences in the timing of the valves or different lengths of the strokes. For every case, additional information on the physical processes taking place is presented in a step-by-step text. Both the animations and the explanations are thoroughly based on the provided bibliography.