Mechagodzilla was constructed in secret by the Bilusaludo and humans in Japan from 2042 to 2046, only to be lost in the final battle between the United Earth and Godzilla in March of 2046.4 However, Mechagodzilla's head remained intact, and its A.I. survived. Over the subsequent 20,000 years, Mechagodzilla's Nanometal gradually spread throughout the surrounding area.