Rockefeller Center holds a place in the hearts of millions of Americans thanks to its annual Christmas tree lighting, NBC Today Show studios, and the storied Radio City Music Hall. And with the Top of the Rock’s sweeping views over Manhattan—from Central Park past The Empire State Building to One World Trade—it’s home to one of our favorite  observation decks in NYC. Entire books have chronicled this inimitable development, a true “city within a city.” Though it seems like we all know 30 Rock like an old friend, here are a few tidbits about the destination that may surprise you.

It’s named for John D. Rockefeller, Jr.

The wealthy philanthropist and business magnate financed the entire project after leasing the land from Columbia University.

The Met Opera was supposed to be the star attraction

Original plans called for a new home for the Metropolitan Opera. After the Crash of 1929, however, the Met backed out.

Rockefeller Center was a major employer during the Depression

Construction took place during the Great Depression, providing 40,000 construction jobs during the the early 1930s.

The Christmas Tree tradition began in 1931

When Rockefeller Center was still a construction zone, the first tree had tin cans and paper garland. Today’s tree is a more luxe affair, with its 50,000 LED lights and crystal star—comprising 25,000 Swarovski crystals.

It was a fallout shelter during the Cold War

Rockefeller Center served as a fallout shelter location during the Cold War, stocking its basements with preparations and supplies.

It really is its own city.

The entire complex encompasses six square blocks, and requires dedicated zip codes. A subterranean Concourse level links many of the buildings, which connect to the city via their own subway station.

It’s a perfect spot to celebrate Independence Day.

The Top of the Rock is open during regular business hours for the Fourth of July (8 a.m. to Midnight), making it one of the finest fireworks-viewing locations in the borough.

You’ve seen it, and thought it was the Empire State Building

The famous “Lunch atop a Skyscraper” photograph, commonly assumed to be showing workers on the Empire State Building, actually depicts 30 Rock.

Rockefeller Center is a museum, too

Art Deco sculptures, murals and architectural embellishments adorn Rockefeller Center inside and out, each tied to the theme of progress. Highlights include sculptures of Atlas and Prometheus, and Jose Maria Sert’s American Progress in the main lobby of 30 Rockefeller Plaza.

It’s a beacon for global unity

The flags lining the plaza hail from every member country of the United Nations, whose iconic headquarters is under a mile away.

Names can be deceiving…

The Rockefeller family’s ownership in the development officially ended in 2001 when Tishman Speyer bought out the remaining holders for a whopping $1.85 billion.