Fortress of Solitude

The Fortress of Solitude is a relic of the planet Krypton hidden in a tesseract sphere in the Andes mountains. It was created by Eradicator when Superman brought it Earth as his base. It was supposed to turn Earth into the new Krypton. Stopping this from happening, the Fortress would stay hidden as Superman's secret base hidden in the arctic as a way to find out information about his past and purpose of Krypton and why he was placed on Earth.