Rockefeller Center is a complex of 19 commercial buildings built by the Rockefeller family and in the center of Midtown Manhattan. It was declared a National Historic Landmark in 1987. It is the largest privately held complex of its kind in the world, and an international symbol of modernist architectural style.

One of the important parts of Rockfeller Center is The Radio City Music Hall. It was buit in 1932. At the time it was the largest and most opulent theater in the world.

The centerpiece of Rockefeller Center is the 70-floor, 872-foot (266 m) GE Building. The famous Rainbow Room club restaurant is located on the 65th floor; the Rockefeller family office covers the 54-56th floors. The skyscraper is the headquarters of NBC and houses most of the network´s New York studios.

Center Art is another remarkable place at Rockfeller Center. A large number of artists contributed work at the Center.

One of the little known but fascinating parts of Rockefeller Center is the underground Concourse. This is an interconnected series of pedestrian passages. The concourse, New York´s largest underground city, contains retail shops, fast food and fine dining.

Rockfeller Center has also one of the most popular observation areas, from the top of it´s highest building.

Sources, related links:
Rockefeller Center - official web site
Wikipedia - Rockefeller Center
Wikipedia - Rockefeller Center Christmas Tree
Wikipedia - Rockefeller Rockefeller family