Haibane Renmei (2002) IMDb
A girl is born from a dream into a world where she is told she is a creature much like an angel, but without any supernatural power. Useless wings grow painfully from her back, her halo is artificial and the new world around her is a single pleasant city, inescapably and inexplicably walled in.
A bleakly philosophical fantasy, more lyrical than dramatic or epic. Excellent character development and low-key philosophy, much more meditative than Cogswell’s escapist “The Wall Around the World” (1953) or Farmer’s To Your Scattered Bodies Go (1971). Manga-based.