|"You've got to hand it to the Fire Nation. They might be tyrants, but they certainly are fine engineers."|
|— Sokka to his father about the barricade.|
The Fire Nation barricade was a large metallic barrier constructed by the Fire Nation in 100 AG as a means to gain control over traffic through the Serpent's Pass during the Hundred Year War; the barricade is situated between the East and West Lakes, therefore limiting traffic effectively.
After Earth King Kuei was overthrown, the military of the Fire Nation, under the command of Admiral Liang, quickly swarmed into East Lake, forcing the Water Tribe forces, along with Aang and his friends, to abandon their defense of a nearby bay. After scuttling the Water Tribe fleet in the center of East Lake and commandeering a Fire Nation patrol vessel, they fled west and later encountered the new barrier built by the Fire Nation.