The Justice League Watchtower was the headquarters of the Justice League of America. The Watchtower was constructed of promethium and used highly advanced Martian, Thanagarian, Kryptonian, and Earth technology. The arrival of Orion and Big Barda added the technology of New Genesis and Apokolips to the systems within. The Watchtower was destroyed by Superboy-Prime and superseded by the The Hall, based on Earth, and Satellite Watchtower in space.