From the Super Mario Wiki
Jiggle Jungle is one of the five continents of the Shake Dimension and the fourth one explored in Wario Land: Shake It! It is jungle-themed, with almost every area filled with Amazon-like plants, and even rivers are found. There are two normal levels in a jungle, the other two normal levels are underwater and in the sky. When Queen Merelda was held hostage, Bloomsday took her role to rule this continent.