Ossus

Ossus was once a teaching ground for the Jedi Order, and was the location of a vast museum of Jedi artifacts and ancient lore. Throughout the Great Sith War, Exar Kun caused a star in the close by Corn Cluster to go supernova, the quake from which would have awful effects on the planet. The Jedi rescue as various artifacts as they could, and had to leavr the rest behind.

The Neti Master Ood Bnar stood over a cache of lightsabers and twisted himself into his huge tree form, present the shockwave and protecting his charge for over four thousands years, until he awakened to fight perpetrator Sedriss during the reign of the reborn Emperor. It is understood that the Jedi Order was formed on Ossus.