Its landmark orange tower has stood guard over Los Angeles' northern gateway for nearly 35 years, a beacon of fun and commerce for generations of thrill seekers. Roller coasters - including Revolution, the world's first 360-degree loop - can be seen from busy Interstate 5, some of the rides roped with neon light. Though visitors see few traces of Six Flags California's Magic Mountain's 35th anniversary - it's eclipsed by parent Six Flags Inc.'s 45th birthday celebration - the air still buzzed as screaming patrons zipped though any of its 16 white-knuckle coasters.