Jedi Temple ( Ilum ) The Jedi Temple on Ilum and the Crystal Caves beneath it was a complex erected by the Jedi Order , one of its earliest endeavors to construct temples across the galaxy . A common pilgrimage site for the members of the Order , the Temple hosted a trial known as the Gathering , wherein students of the Jedi academy retrieved the kyber crystal which would power their personal lightsaber . History . The Temple was constructed at the behest of the Jedi Order , and became home to the ritual known as the Gathering . During the Clone Wars , Grand Master Yoda brought with him a group of Jedi students intent on locating their own kyber crystals to use in their lightsabers . When the Galactic Empire emerged victorious from the war , the new Galactic Emperor made it one of his first orders of business to establish a garrison at the Temple . The newly christened stormtrooper s killed all Jedi that hoped to escape to Ilum , securing the building promptly . While the Temple remained structurally sound , the Imperial Army erected a five meter thick , reinforced plasteel containment vessel over the entrance to ensure the complex was inaccessable to any who wished to enter . Layout . Erected over the largest mouth of a vast cave system in the mountains of Ilum , the Temple was meant to fortify and protect the entrance to the caves and give visiting Jedi a place to rest and recover from the harsh environment outside . The mouth of the cave was located at the base of a towering cliff face , and the Temple itself was constructed around that site from natural stone . The exterior of the Temple was marked by reliefs and sculptures denoting legendary figures and moments in history of great import to the Order . Tall , narrow windows of multi - colored glass punctuated the upper levels of the Temple ' s rounded walls to let in natural light . The great doors of the Temple were constructed of the light - absorbing stone mined form the caves and accented by a silvery alloy . Because of the Temple ' s infrequent use , the doors often became obscured by debris , fallen ice , or banks of snow . Instead of maintaining it , the Order came to view the obstruction as a portion of the Gathering rite , requiring visiting Padawans to work their way into the Temple with the sacrifice of their physical strength . The Temple ' s doors opened on to the facility ' s main chamber , a towering rotunda carved up into the mountain itself . The center of the room was dominated by two hooded statues of lightsaber - wielding Jedi , ringed by carved obelisks that sprouted from the rounded floor . The exterior wall of the chamber contained access to passages and several smaller rooms that went up several levels ; a storage level existed below the Temple proper . The wall opposite of the Great Doors contained the entrance to the cave systems that penetrated deep into the mountain ' s heart . A natural flow of water poured slowly from the upper heights of the Temple ' s ceiling , creating a dense wall of ice over the Temple mouth . To melt the ice , the Jedi constructed a complex mechanical cradle to hold up a huge kyber crystal near the Temple ' s domed ceiling . When focused on the ice fall , the sunlight would melt the ice and reveal the entrance to the caves , if only until sunset when the falls would freeze over once more . The mechanism only worked every seventeenth day , when the sun rose over the Temple .