... Midgar
You can get the secret ending by finding all Dalmation Puppies, locking all worlds (including 100 acre woods) and completing the Hades Cup. You don't need to get the Ultima Weapon or Beat Sephiroth (because I didnt and I got the vid, but I saved at the last rest so Im gonna go beat Sephiroth later)
I'm really quite confused about it all, I just dont want to wait too long for KH2.