The Grand Conservatory is a facility built by the Echidnas of Angel Island following the defeat of the first Enerjak, located in the Marble Garden Zone. It was built as a storehouse for the technology that the Echidnas rejected in hopes of preventing another one of their own from becoming as twisted as Enerjak. However, the Conservatory's creation sparked a split between the Echidnas of Angel Island, thus creating the Dark Legion. Since that time, the Grand Conservatory has been raided by Dingoes and the Dark Legion itself, as well as serving as a hiding place for equipment belonging to the Brotherhood of Guardians. Most of the time, however, it remains vacant, waiting for someone else to come along and exploit the technology contained within.
After Dimitri was buried beneath the ruins of his Dark Tower, the High Council of Echidnaopolis made his brother Edmund the first Guardian, entrusting him with the protection of their city and the people. A referendum was held in which the majority voted to ban excess technology, with the hopes that it would prevent another machine such as the Chaos Syphon that had driven Dimitri mad from being created. Many citizens complied, but those who refused to give up the technology of their heritage joined together under Dimitri's son, Menniker, to become the first generation of the Dark Legion. The technology that was collected was stored in the Grand Conservatory, which was then sealed up. (StH: #35, #36, KtE: #1)
Storage depots similar to the Grand Conservatory were later breached by the Dingoes, who stole nuclear weapons the Echidnas had built centuries before, with the intent of turning them against Echidnaopolis. Guardian Hawking, taking plans from the Conservatory, constructed a weapon to shoot down the nuclear missiles before they hit the city. He then constructed the Hyper-wave Projector to transport Echidnaopolis and the other inhabitants of Angel Island to separate pocket zones, needing time to clean up the island from the nuclear fallout. (KtE: #5)
Dark Legion Stronghold
Knuckles the Echidna would later penetrate the facility created by his ancestors after Archimedes brought the Chaotix to the Grand Conservatory in order to lure Knuckles there. After breaking through a series of highly advanced defenses, Knuckles found his friends safe. However, Enerjak had recently managed to escape his imprisonment from beneath Mt. Fate, and put them under mind control before he banished Knuckles and Archimedes to Sandopolis, moving himself and the Chaotix to the new Nekronopolis at the same time. (KMS: #1, #2, #3)
Later, the Dark Legion seized the Grand Conservatory as a base while preparing to unleash the Quantum Beam weapon on Angel Island. Their occupation was broken up by a Brotherhood attack led by Guardian Mathias, who ended up dying during the assault as the Quantum Beam was fired. (SSS: #14)
Later, the Brotherhood would use the Conservatory as a hiding place for a weapon designed to kill Enerjak if he ever was reborn, which Locke sought to recover when Knuckles was brainwashed by Dr. Finitevus into taking on the role. Aided by Sonic the Hedgehog and Julie-Su, he broke through the Destructix, Scourge the Hedgehog, and Fiona Fox, whom Finitevus had set on guard duty. Locke's plans were then ruined when Sonic himself destroyed the weapon, refusing to kill Knuckles just to achieve victory. (StH: #181, #183)