Angel Island

Angel Island (originally known as the Floating Island) is a large landmass which floats high above the planet's surface. Originally a part of the continent of Downunda, the Echidnas living in the city of Echidnaopolis decided to use the powers of 12 Chaos Emeralds to lift their city off the surface to avoid destruction by a White Coment. Since then, Angel Island has been the home of many different species, the two largest being the Echidnas and the Dingoes. It is currently under the rule of the Dr. Eggman-backed Dingo Regime.

Ascension
A group of echidnas, having set out from their homeland of Albion, eventually settled in a region of Downunda and built the city of Echidnaopolis. The technologically-advanced city thrived on the mainland until two scientists, Kayla-La and Jordann, discovered a comet that would soon impact directly on the city. Desperate to save their home, the two developed and proposed a plan to physically move the city out of harm's way. Collecting as many of the powerful Chaos Emeralds as they could, the scientists harnessed their energy and, with the fire-ants working to loosen the foundation, lifted Echidnaopolis and the surrounding land into the air and out of the path of the White Comet, saving it from destruction and forming what was then known as the Floating Island. A large crater marks its former place in Downunda.

Dimitri and Edmund's Plan
Generations later, another pair of scientists sought to return the city to its original ground-bound state. While the energies of the Chaos Emeralds weren't completely understood, Edmund and Dimitri theorized that, should the energy be gradually drained, the decent of the island could be controlled and allow it to slowly, safely return to the mainland. The two developed a device called the Chaos Syphon, capable of draining away Chaos energy, and proposed their plan to the gathered council. However, in part due to one councilman's personal political goals, the plan was rejected, officially on the grounds of being too dangerous a move.