The Foundry, also known as the Ring Foundry, was a subterrainean chamber complex on the planet Oa and was crafted by the Guardians of the Universe as a means of creating new Power Rings and Power Batteries for their Green Lantern Corps. According to the Book of Oa, the forging of a Power Ring was a feat that was most arduous even for a Guardian due to the massive as well as lethal levels of willpower that needed to be sustained during the process. Willpower was used as the ore in the crafting process which was used to cast a Power Battery into a mold whereupon the Power Ring was summoned from the lamp as it was ignited. This region on Oa also contained a large number of secret projects that the Guardians had created in their long existence. These included holding tanks that contained the P