Conceived by the oil magnate John D. Rockefeller during the Great Depression of the 1930s, Rockefeller Center occupies nearly 22 acres of prime real estate with plazas, concourses, and shops. Its central cluster of buildings, between 5th and 6th avenues and 47th and 50th streets, consists of smooth shafts of warm-hued limestone, streamlined with glistening aluminum. The center is a capital of the communications industry, containing the headquarters of NBC, several major publishing companies, and the Associated Press. Sprawled on a ledge above the lower plaza is the great gold-leaf statue of the fire-stealing Greek hero Prometheus. The plaza's trademark ice-skating rink is open from October through April; in December an enormous live Christmas tree towers above.