Subway

The Megakat City subways was used by citizens to commute throughout the city. During one infamous incident, however, a giant bacteria monster, one of Dr. Viper’s creations, attacked and ate an entire subway train full of innocent passengers despite Razor’s attempt to prevent it.

In the unfinished episode The Doctors of Doom, Dr. Viper’s mutant grub worms would’ve tunneled through the subway to get to the Megakat Thermonuclear Plant.