Pig Fortress

A Pig fortress is what the Bad Piggies build to protect themselves against and slow down the Birds from retaking their eggs. Pig Fortresses can be in any terrain: Mines, Jungles, Clouds, Normal Terrain, Construction sites, Desert, etc. Most of them are buildings, but some are seen to be methods of transport, for example, a tank-shaped structure in one level and wooden cars in a Golden Egg level. They mainly include materials such as ice, stone, and wood. They eventually get stronger in the later levels.

Terrains

 * 1) Plains (Worlds 1 and 4)1-1.png and ice.]]
 * 2) Deserts (World 3 and 5)
 * 3) Bamboo Gardens (World 2)
 * 4) Jungle (World 6)
 * 5) City (Worlds 7 and 11)
 * 6) Clouds (World 8)
 * 7) Construction (Worlds 9-11 [based on themes from worlds 1-7])
 * 8) Western (Worlds 12-14)
 * 9) Cave (Worlds 15-17)
 * 10) Birthday (World 18-19)
 * 11) Bad Piggies Theme 1: Ground Hog Day (World 20)
 * 12) Bad Piggies Theme 3: When Pigs Fly (Worlds 21 and 22)
 * 13) Beach (Surf And Turf Levels 1 to 15)
 * 14) River (Surf and Turf Levels 16 to 30)
 * 15) Stormy Mountainside (Surf and Turf Levels 31 to 45)