<a href="http://info.sonicretro.org/File:Stt_gg_us_manual_00_01.jpg" target="_blank">Sonic Triple Trouble takes place on Mobius.</a> I'll try and itemise the alternate-canonical settings I remember: <ul><li>Fleetway Sonic The Comic has Mobius as a seperate planet entirely, existing many light years away from Earth. Kintobor originally came there in his personal spaceship before turning into Robotnik. Amy Rose actually travels to Earth in one story (and meets Tony Blair, lulz). STC never had any humans except Robotnik, given that it was cancelled shortly after SA1's release.</li><li>OVA was set on bizarro-world "Planet Freedom"... which actually looked to be a far-future post-apocalyptic Earth, as Sonic lived in a crashed overgrown 747, and Robotropolis was built next door to the ruined, flooded ruins of what seems to be New York. Other humans living in crystalline hover-car future cities in the sky, although their leader appears to be the President of Bolivia.</li><li>Archie / SATAM has "Mobius" explicitly as a far-future post-apocalyptic Earth.</li></ul> Before SA1 I never considered there to be any humans besides Robotnik in Sonic's world. I still recall making a "What. The. Fuck." face on seeing the moonwalking police in Station Square for the first time. Don't consider them to have been implied before SA1; as far as I was concerned, the ancient West Side Island civilizations were obviously animal ones, no question.