Stars shape the morphology of the medium around them through stellar winds. In this fashion, each star creates a bubble around itself, which changed over time as the star evolves. In this fashion, each circumstellar bubble carries not only the evidence of the current condition of the star but also of its previous evolution. Furthermore, the characteristics of these bubbles can make themselves felt even after the progenitor star has ceased to exist; for it is inside these bubbles that phenomena such as supernovae and gamma-ray bursts take place.

Through the application of numerical magneto-hydrodynamics, we can create simulations of these circumstellar bubbles that can be compared to observations. These models, which started as simple 1-D hydrodynamical experiments, have been improved upon over time to include additional physics, such as the presence of dust and the influence of interstellar magnetic fields.

In this talk, I will give a general overview of the characteristics of circumstellar bubbles as well as a number of specific examples to demonstrate how the numerical models can be used to explain observed phenomena.