Stars with initial masses of 8Mo and above are considered massive stars. These stars have luminosities of 10^3 to 10^6 Lo and above. While on the main-sequence, these stars are spectroscopically identified as types O and B, while later evolutionary stages encompass the enigmatic Luminous Blue Variables (LBVs), red supergiants (RSGs), and Wolf-Rayet stars (WRs). These stars end their lives as spectacular core-collapse supernovae.