Released in 1989, the Sega Mega Drive or Sega Genesis heralded the coming of the 16-bit era. It also inaugurated the Console Wars of the 1990s. It was the first successful 16-bit system, with a 14-year lifespan second only to the Nintendo Game Boy. Games continued to be released internationally as recently as 2002. Genesis games are re-released even today as part of collector's editions for the PS2, PSP, and other systems. They are even available for download on the Nintendo Wii Virtual Console.
The Genesis was developed with the American market and consumer in mind. In addition to porting over popular coin-op games, Sega executives worked hard to lure developers away from Nintendo. These efforts were often successful, Nintendo Exclusivity Clause not-withstanding. Sega marketed the Genesis as hip, cool, and edgy. Sonic, released in 1991, had attitude. Sega also focused attention on its better graphics, speed, and sound, especially after the release of Sonic. The Genesis could do things that the NES simply couldn't.
In 1991, Sega released the Mega CD or Sega CD, which was a CD-ROM add-on for the Genesis that allowed gamers to play CD based games as well as audio CDs.