These following locations remind me of Sandopolis:
- This is because they are not only ancient egyptian themed but also show heavy evident of Echidna culture. My theory that when Angel Island risen with the remaning echidna's of Knuckles tribe, they populated the island and started there own culture. Perhaps the Echidna's of Marble Garden Zone and Hidden Palace Zone were the oldest and original Knuckles tribe echidnas while the echidna's of Sandopolis decided to become less Aztec and more Egyptian in culture.
However I do wonder where the Sonic Adventure 2 stages I listed take place. Was it all in Sandopolis? Did Robotnik sneak a base on his island again? Since Angel Island wasn't mentioned this makes it difficult to say. Sand Hill could also of taken place in Sandopolis. Lets say in Mystic Ruins, Angel Island landed North of the trains station and Tails' home and the trolly goes around the island which means it also landed West of the jungle, my guess Sonic and Tails has found another underground entrance onto the island into the desert zone of Angel Island. Either that or the cliffs to the west were just cliffs surrounding the jungle. So where do you think the Egypt Echidna levels in Sonic Adventure 2 took place? Sandopolis on Angel Island or somewhere else?