Intersection. The word is a perfect fit for JR, the French-born photographer who started out as a teenage graffiti artist, switched to a camera, began pasting large (and largely illegal) photographs on walls all over the world, and then, inspired by Diego Rivera’s murals, developed into a roving portraitist of cities and their citizens. Working at the intersection of photography, street art, and the impromptu happening, JR pounds the pavement, collecting passersby for group portraits. When he has enough of these portraits he digitally collages them into one epic work—an intersection, you might say, of urban diversity and commonality, an open-air choir in soaring shades of gray.

JR has “chronicled” neighborhoods as diverse as the Paris suburbs of Clichy-sous-Bois and Montfermeil, and the city of San Francisco. He now returns to the Big Apple (which he has previously portrayed in a number of other projects) with Chronicles of New York City. It opens on October 4 in the Great Hall at the Brooklyn Museum, where the work will cover 20,000 square feet. More than a thousand New Yorkers are in the image, and audio recordings allow viewers to hear each person’s story. Meanwhile, at New York’s Perrotin gallery, “The Chronicles of New York City: Sketches” is up and running. The photographs that make up the show, printed in traditional sizes, do not picture the entire collage but pieces of it, powerful in themselves. Look at the detail above, how it catches the city’s grid-like intensity, an acropolis of intersections, as well as its upward energy, symbolized by a single dancer balanced on the corner of a building, taking a giant step. —Laura Jacobs