For six seasons, a blog nobody could trace ruled the Upper East Side. Gossip Girl ran on The CW from the 19th of September, 2007, to the 17th of December, 2012, 121 episodes in all. Josh Schwartz and Stephanie Savage created it from Cecily von Ziegesar's novels, and Kristen Bell was the voice of the anonymous narrator. It followed Serena van der Woodsen, Blair Waldorf and their friends and rivals through private school, family scandal, weddings and the question everyone asked: who is Gossip Girl? And it really was filmed on these streets, though most of its interiors were sets at Silvercup Studios in Queens. This walk follows the story down Fifth Avenue in rough season order, from the school steps to the final wedding in Central Park. Then it flashes back to season one, and ends where the whole thing began. This is an unofficial fan walk, not made with or endorsed by The CW, Warner Bros. or the show's makers. It's one of our self-guided walking tours, about 5.8 kilometers from the Museum of the City of New York to the Palace hotel on Madison Avenue.

Before you set off

Allow about an hour and twenty minutes of walking, and closer to two hours with the stops. The route is flat almost all the way, mostly down Fifth Avenue beside Central Park, with one longer stretch through the park itself. To reach the start, take the 6 train to 103rd Street at Lexington Avenue, about 600 meters away, or a bus up Fifth or Madison Avenue. At the end you're close to the 51st Street station on the 6 and the Fifth Avenue-53rd Street station on the E and M, and Grand Central is about 700 meters farther on. Two stops are private homes and one is an active church, so stay on the sidewalk, keep your voice low and don't block doors or canopies. The museums keep their own hours, so check before you go if you want to step inside. Spoilers ahead for the whole series, including who Gossip Girl turns out to be.

Museum of the City of New York

You're on Fifth Avenue between 103rd and 104th Streets, facing the Museum of the City of New York. It's a real, working museum, founded in 1923. The neo-Georgian building in front of you was designed by Joseph H. Freedlander and completed in 1932, and it became a city landmark in 1967.

Now look at the front steps. In most episodes of Gossip Girl, the show used these steps as the outside of Constance Billard and St. Jude's, the private school where the story's teenagers spend their days. Constance Billard isn't a real school. The museum gave it a face, and the show's cameras did the rest.

These steps saw plenty of drama. In season one, episode fourteen, Jenny Humphrey tips yogurt over Blair Waldorf right here on the front steps. In this school, the steps were a stage, and everyone was watching.

Not everything happened here, though. The school courtyard you saw on screen was a set at Silvercup Studios. And in season two, the school scenes moved across the river, to Packer Collegiate in Brooklyn.

The story begins with school. But it's really about the families waiting at home, a few blocks south, in the apartments along Fifth Avenue.

The first of those homes is Blair's. Walk south on Fifth Avenue, staying on the building side, to the block between 95th and 94th Streets. Look for number 1136, a building with a canopy over its door. About ten minutes.

1136 Fifth Avenue (Blair's)

You're in front of 1136 Fifth Avenue, a private prewar apartment building with a canopy over its entrance. People live here, so stay on the sidewalk and keep the doorway clear.

Throughout the series, the show used this building as the outside of the Waldorf penthouse, Blair's home. Whenever the story headed home to Blair, this canopy and this stretch of Fifth Avenue told you where you were. In season one, episode seven, Nate Archibald and his father have a fight right outside.

Here's what the camera didn't show you. The penthouse itself was never inside this building. Those rooms were sets, built and shot at Silvercup Studios in Queens, like most of the show's interiors. The real building only lent its front door.

Gossip Girl filmed its outdoor scenes on real Upper East Side streets, so what you're passing looks the way it did on screen. Behind these doors, though, live ordinary New Yorkers, not the Waldorfs.

Think of this stop as Blair's home base. She'll pass through the rest of this walk at the center of almost every scene: holding court at the Met, marrying a prince on Madison Avenue, and finally marrying Chuck Bass, in Central Park.

But first, the end of season one, and a wedding. Serena's mother, Lily, is about to marry Bart Bass, and the ceremony takes place in one of the grandest gardens on Fifth Avenue. Keep walking south on Fifth to the corner of 91st Street. The mansion is on that corner, with its garden behind the railings. About four minutes.

Cooper Hewitt (Carnegie Mansion)

You're at the corner of Fifth Avenue and 91st Street, outside the mansion Andrew Carnegie completed in 1902. The architects were Babb, Cook and Willard. Carnegie lived here until his death in 1919. Today it's the Cooper Hewitt, the Smithsonian's design museum, which opened in this house on the 7th of October, 1976. Look through the railings along 90th and 91st Streets and you'll see the garden.

That garden is where season one ends. The finale, called Much I Do About Nothing, aired on the 19th of May, 2008. In it, Serena's mother, Lily van der Woodsen, marries Bart Bass in the mansion's garden. Bart is Chuck Bass's father, so this wedding joins two of the show's families.

It's a fitting place for it. The show's Upper East Side was a world of old money and new money, grand houses and grander parties. Here, the backdrop was Andrew Carnegie's real home. On screen it simply looks like the kind of place Lily van der Woodsen would get married.

In Gossip Girl's world, a wedding was never just a wedding. It was the event everyone would be talking about by morning, and Gossip Girl would make sure of it.

From here, the story spreads across all six seasons. The next stop is the place Blair ruled at lunchtime. Walk south on Fifth Avenue, to 82nd Street. The great steps of the Metropolitan Museum of Art are on your right. About ten minutes.