The Church places prime value to Hubbard’s volumes of works and because of this has instituted the CST to “engrave the entire corpus of Hubbard’s original texts on steel plates.” The most famous example is the Trementina Base, an underground vault built into a mountainside near Trementina, New Mexico. It is marked by a CST logo visible only from a high altitude and was built in the late 1980s. Former members claim that the purpose of CST's archival efforts is to ensure that Hubbard's work survive a nuclear apocalypse and reform civilization. The church believes that these plates will last beyond a thousand years and that Hubbard’s teachings will be vital for "rebuilding civilization," in the event of global turmoil. Former members of the church also claim that the symbols in the logo are “guide markers for Scientologists returning from other parts of the universe," according to "Scientology in Popular Culture: Influences and Struggles for Legitimacy."