  Massive stars lose a large fraction of their original mass over the course of
their evolution. These stellar winds shape the surrounding medium according to
parameters that are the result of the characteristics of the stars, varying
over time as the stars evolve, leading to both permanent and temporary features
that can be used to constrain the evolution of the progenitor star.
  Because long Gamma-Ray Bursts (GRBs) are thought to originate from massive
stars, the characteristics of the circumstellar medium (CSM) should be
observable in the signal of GRBs. This can occur directly, as the
characteristics of the GRB-jet are changed by the medium it collides with, and
indirectly because the GRB can only be observed through the extended
circumstellar bubble that surrounds each massive star.
  We use computer simulations to describe the circumstellar features that can
be found in the vicinity of massive stars and discuss if, and how, they may
appear in GRB observations. Specifically, we make hydrodynamical models of the
circumstellar environment of a rapidly rotating, chemically near-homogeneous
star, which is represents a GRB progenitor candidate model.
  The simulations show that the star creates a large scale bubble of shocked
wind material, which sweeps up the interstellar medium in an expanding shell.
Within this bubble, temporary circumstellar shells, clumps and voids are
created as a result of changes in the stellar wind. Most of these temporary
features have disappeared by the time the star reaches the end of its life,
leaving a highly turbulent circumstellar bubble behind. Placing the same star
in a high density environment simplifies the evolution of the CSM as the more
confined bubble prohibits the formation of some of the temporary structures.
