|The information in this article comes from Marvels, warlord of mars and is not written by Edgar Rice Burroughs.|
The Ebony Island was the floating city of The Great One and his Council of Five. It normally sat in a crater within a great volcano on Barsoom, but the city could float when needed! This city is covered in weapons, radium canons and mysterious unknown weapons, it also had an electromagnetic field that detonated weapons before they could hit the city. The Fortress was eventually destroyed by the forces of Helium.