Fortress of Solitude

Superman's Batcave Many years ago, Superman placed himself into a self-imposed exile from the planet Earth. During this journey, he met an aging alien known only as the Cleric. The Cleric recognized Superman as the Last Son of Krypton and gave him an ancient Kryptonian artifact known as the Eradicator. The Eradicator represented the sum total of all Kryptonian knowledge, lore and culture. Superman brought the device back to Earth, but when it began behaving strangely, he buried it deep down in a fissure in Antarctica. The Eradicator was still active however, and it opened up a dimensional portal and extracted various resources that it used in an effort to recreate Krypton on Earth. This also included the creation of robotic servants, patterned after the maintenance droids that once serviced the House of El on Krypton.