Here’s How They Made La La Land’s Extravagant Opening Musical Number

La La Land, the new movie musical with Emma Stone and Ryan Gosling, starts in gridlock. The scene: a freeway ramp on a blazingly sunny L.A. day. Cars glitter far into the horizon. Horns honk. And then the music picks up.

That opening song-and-dance number, “Another Day of Sun,” is the film’s ode to the city of Los Angeles, a world of endless possibility, constant beauty—and repetitive disappointment. It was also a costly and complicated scene to shoot, resulting in six minutes of busy action involving dozens of actors on a freeway ramp they had to shut down for a whole weekend.

“It was tricky. It was touch and go for a bit,” explains director Damien Chazelle. The show kicks into gear when one woman gets out of her car, bursting into song. Others join, and soon the entire roadway is filled with dancers backflipping off of car hoods and pirouetting through the stalled traffic. The first take was a disaster; the cranes were in danger of knocking into dancers’ heads; the choreography brought them leerily close to the ramp’s edge. On the second go-round, however, they managed to make it work.

“We got there at night and then we’d shoot until the sun came back down,” Chazelle says. They shut down the whole freeway through the weekend—a feat of permit magic. And then there’s the magic of the exuberant dancing, of the song’s bombast, and of the way the scene sets up the personality of Los Angeles itself, a city of dreamers clinging to the shot at a future “that may or may not happen,” as composer Justin Hurwitz puts it.

“The opening number is a perfect example of that dichotomy, because on the face of it it’s a very exciting, happy song, but there’s a lot of melancholy in it as well,” he says. You’ll find that melancholy right there in the title: “Another Day of Sun.” It’s upbeat, but there’s something a little weary about it too.

For lyricists Benj Pasek and Justin Paul, that push-and-pull informed their approach. “What Damien inspired us to capture was that there’s this difference between L.A. and New York,” Paul explained. “In New York, you grind and grind to pursue your dreams and accomplish what you’re hoping to accomplish, and you get up the next day and it’s muddy and gross and the snow is just turned to black ice.”

Meanwhile, L.A. may also be a constant struggle, but it’s also constant blue skies. “You pursue that dream, and you go to bed and get up the next day, and it’s a gorgeous day,” Paul says. “It encourages you in one breath, and in another breath doesn’t acknowledge that you just failed miserably. You wake up and it doesn’t match your mood. It’s a bright and shiny day. And you’re like, ‘Wait a second!”