The Teenage Mutant Ninja Turtles (often shortened to TMNT or Ninja Turtles) are a fictional team of four teenage anthropomorphic turtles, who were trained by their anthropomorphic rat sensei in the art of ninjutsu and named after four Renaissance artists. From their home in the storm sewers of New York City, they battle petty criminals, evil overlords and alien invaders, all while remaining isolated from society-at-large.