It's about a girl who lives in a world that is floating, and she doesn't know about her mother. I think she knows her father. Anyway, her mother is basically the life source of the world(which I think is also some sort of spaceship) and chose to go into a chamber and give her life to keep the world from ending. The girl falls in love, and at the end she finds out about her mother and that her mother's energy is running out ,and the world needs a new life source. She decides to be the new life source and the story ends when she goes into a chamber next to her mother. I watched this a long time ago, I thought I made it up but a lot of people are telling me they have watched it before but cant remember the name. I thought it was something called 'Ark' but I don't see any movies with that name. Help please...?
And I don't think its Atlantis: The Lost Empire. It was really modern looking, and like I said, EVERYTHING is just suspended in the air, chunks of ground floating.