Balamb Garden was discovered by Cid and Edea Kramer prior to the events that take place in the game. They built onto the ancient structure and turned it into a school.
Gardens are massive structures that were created long ago by a long dead civilization. They are the size of a small city and were thought to originally be a form of shelter in case of cataclysms.
The three reimaining Gardens all have a mysterious trasnportation system that allows them to float over mild terrain.
Balamb Garden is managed by Cid, the headmaster of the Garden and commander of SeeD; a mercenary group also founded by the President. The facility is funded by a mysterious person named Norg.
Balamb Garden was the first Garden found and converted into a school. The educational programs at this Garden specialize in the use of Magic along with basic combat and weapons trianing.