Encyclopedia Barsoomia Wiki
The information in this article comes from The John Carter of Mars sunday strips and is not written by Edgar Rice Burroughs.

The forbidden Plateau of Eo is plateau south of Helium. It is home of the wizard of eo, the green martian Vovo. When Dejah Thoris was turned to stone Sola brought her and John Carter here because nothing was impossible for the wizard. The top of the plateau is covered in a wild and dense jungle! Here upon this plateau is the the city of Eo built Vovo and his mechanical men.