The Cloud Tower, also known as "Cloud Tower School for Witches", is a towering, twisted castle that is a boarding school for Witches and the most prestigious educational institution for Witches. At Cloud Tower, witches learn about witchcraft. It is the magical competitor and rival of Alfea. Its headmistress is Headmistress Griffin. The campus itself is a huge and vast living organism that had been created in ancient times by powerful sorceresses.