The Well of All Sparks housed the AllSpark. In the past when protoforms emerged they would brave the terrors of the Underworld to leave, but in the era of the caste system there a Cybertronian was taught how to transform, assume their most natural alternate mode and were put into a Guild. During the Great War, the AllSpark was ejected into space, and the Well remained empty until Optimus Prime journeyed through it to the core to purge it of Dark Energon. Alpha Trion had the Ark built in the Well, and there it launched into space.
The Well of All Sparks came into being when Megatronus killed Solus Prime, and her corpse unexpectedly melted its way underground to the core of Primus and Cybertron, becoming the Well of All Sparks. After the climactic battle which splintered the Thirteen Primes, the mortally wounded Onyx Prime chose to travel to the Well, where the presence of Primus would sustain him forever. He would use his Triptych Mask to enable the new race of Cybertronians to have as much diversity as Primus had created the Thirteen with. Micronus Prime chose to accompany his friend to his eternal retreat, and Thirteen chose to accompany them so that he would be reborn as one of these new Cybertronians so that he would be able to help them by experiencing their lives. After Thirteen, Micronus, and Onyx vanished into the Well, the power of the Triptych Mask sent forth a universe-spanning beam which scanned and transmitted back information on the universe's life on which new Cybertronians could be modeled. For the next three days, new Cybertronian lifeforms of all shapes and sizes emerged from the Well. Thereafter, the Well would occasionally send forth new beings to replace the dead or simply to introduce new life to Cybertron until the planet became a lush, rich world.
During the Golden Age, replicas of the Well were built on many of Cybertron's new colony worlds. These miniature Wells were activated by a "torch"- ignited from the original Well on Cybertron then carried through a space bridge to the new Well. When activated, the new Wells could produce energon as well as give birth to new Transformers just like the original well could. The first replica was built on Archon. The design was mimicked on countless other worlds throughout the galaxy, making them entirely self-sufficient.Team Prime restored Cybertron. Though life on Cybertron was unable to come. Optimus went to retrieve the AllSpark with Wheeljack while the other Autobots investigate strange events like two new Predacons coming around. Their mission was at a halt when Megatron (Unicron inside Megatron's body) attacks them. Unicron planned to destroy Cybertron once and for all by destroying the planet's core. He made an army of Terrorcons and headed for Cybertron's core. Optimus Prime came in time to stop the chaos bringer by trapping him inside the AllSpark's container. After that, Optimus said that he must complete his mission of returning the AllSpark to the well. As his fellow Autobots watched him fly into the Core, Optimus opened the Matrix of Leadership and entered the core. Suddenly, Sparks began to fly from the sky. The Autobots watched in amazement as the sparks, including Optimus', shine out.
- The original Primes saw the activation of the well. Team Prime also saw the sparks fly out after Optimus flew to the core. As the sparks flew from the well, a red light sparks around, presumably Optimus' own spark was the red spark.