The xel'naga constructed a temple here. The Dark Templar visited it during their journey away from Aiur but didn't locate it. Terran exploration, including a 2501 expedition led by Jake Ramsey, also failed to uncover it.
Two years later, Ramsey and the preserver Zamara directed Prelate Zeratul to the temple. There he witnessed the release of an energy creature and followed it to a gathering of other creatures in space. The prelate went through the wormhole formed by the creatures.