1251 Avenue of the Americas
…which was the second tower completed (1973) and is the second in height (674 ft and 51 stories). The "Z" Building, the shortest and the youngest, is 1211 Avenue of the Americas with 45 stories (592 ft). 1251 is the second-tallest building in the whole of Rockefeller Center, after 30 Rockefeller Plaza. Despite being one of the…