  Massive stars evolve across the HR diagram, losing mass along the way and
forming a variety of ring nebulae. During the main sequence stage, the fast
stellar wind sweeps up the ambient interstellar medium to form an interstellar
bubble. After a massive star evolves into a red giant or a luminous blue
variable, it loses mass copiously to form a circumstellar nebula. As it evolves
further into a WR star, the fast WR wind sweeps up the previous mass loss and
forms a circumstellar bubble. Observations of ring nebulae around massive stars
not only are fascinating, but also are useful in providing templates to
diagnose the progenitors of supernovae from their circumstellar nebulae. In
this review, I will summarize the characteristics of ring nebulae around
massive stars throughout the HR diagram, show recent advances in X-ray
observations of bubble interiors, and compare supernovae's circumstellar
nebulae with known types of ring nebulae around massive stars.
