From Sonic Retro
In the history of Sonic's world, the Babylonians were a technologicly advanced civilization whose legacy forms the basis for the storylines of Sonic Riders and Sonic Riders: Zero Gravity. They were the creators of Babylon Garden and the Arks of the Cosmos, as well as an early form of Extreme Gear. The Babylon Rogues believe themselves to be descended from ancient Babylonians.
In Sonic Riders, just before the Splash Canyon race, Tails recounts an old legend that the Babylonians were cast down from the sky and scattered because they had angered the Gods. Zero Gravity reveals the hidden truth behind this myth: that the Babylonians had an extraterrestrial origin, and travelled to Sonic's world aboard a starship (Astral Babylon). However, some sort of accident or instability with the Arks of the Cosmos forced them crash-land on the planet. Over time, the stranded Babylonians lost their high technology and even the knowledge of their own history, leaving behind only misunderstood legends and the occasional glittering artefact, like the crystalline cube passed down by Jet's father.
As their ancient simulation, Angelus the Gatekeeper, indicates, the ancient Babylonians resembled birds crossed with genies. Amy speculates that the tradition of "wishing upon a star" may have originated from the grounded Babylonians' yearning to return to space and get back ot their home world.
|“||After the floating continent fell to earth, the people had to live down here among us. But they one day longed to return to the sky, so they left keys to point the way. So that one day, their descendents might regain what they had lost.||„|
— Blaze the Cat, explaining the Hidden Islands' ruins
In Sonic Rush Adventure, Sonic and Tails explore the parallel Sol Dimension where Blaze and Marine live. Tantalising hints from an ancient civilization can be found around the Hidden Islands of the game's vast ocean - the most concrete of which comes in the form of a lost floating city, Sky Babylon. One of their ancient altars raises Coral Cave - resting place of the Jewelled Scepter - from the sea, and their old writings indicate that they built the submarine defences beneath what has become Captain Whisker's Pirates' Island.
The name "Sky Babylon", as well as the suspiciously similar story of their fall from the heavens, implies that these ancient works may point to the Sol Dimension counterparts of Sonic's world's Babylonians.