In 1964, the married artists Christo and Jeanne-Claude moved out of the Chelsea Hotel and into the top two floors of a loft on Howard Street, in SoHo. Sure, they were broke—the hotel proprietor said they could pay him back later—but they were jazzed about their new digs. The place had big windows and an airshaft. (Later, they bought the building; it was the seventies.) Eventually, the airshaft became a storage unit, and it was there, in 2018, that Christo’s studio manager discovered a scale model, complete with electrical wiring and preparatory drawings, for a project the artist had forgotten about from half a century earlier. Eureka!

The other day, at the Gagosian in London, several art installers were hoisting ropes and clambering up ladders, in order to mount the work in a gallery for the first time. The piece, “Air Package on a Ceiling,” was designed in 1968 for the Institute of Contemporary Art, in Philadelphia, and involves a giant sheet of plastic suspended from the ceiling and crossed by ropes that make it bulge and fold. (It never reached the I.C.A., owing to technical concerns.) The effect is disorienting, as if the air had turned solid. Overseeing things was Christo’s nephew, Vladimir Yavachev, who was dressed in layers of black. “I mean, it’s up there—it’s not falling,” he said, peering at the plastic.

Yavachev began working with Christo in 1990, when he was a teen-ager, and newly freed from the constraints of Communist Bulgaria. He arrived in New York having never met his uncle, who had escaped the Eastern Bloc years earlier, by bribing a customs officer, and had never returned. “In Communist Bulgaria, there was a word for it,” Yavachev said. “You don’t become an immigrant, you become a nevuzvrashtenetz, which means ‘the one that can never come back.’ ” Christo and Jeanne-Claude travelled the world wrapping things: cars, islands, the Sydney coastline. “The enthusiasm was incredible,” Yavachev said.

Christo died in 2020—Jeanne-Claude in 2009—but the duo left detailed instructions for the posthumous installation of “Air Package” and other works, including “L’Arc de Triomphe, Wrapped,” which Yavachev completed in 2021. At eighty, Christo was involved in the final planning. By the time the installation began, his presence was greatly missed. “He had always been like a jackrabbit running around to see a project from every point of view that you can,” Yavachev said. “The way he would look at them, it was like a little kid looking at a cake, like you want to eat it. It was always like this, always ‘Look, look, look, look!’ ”

“I used to hunt in a pack, but we all drifted apart after college.”

Cartoon by Ellie Black

In the gallery, a man in a ball cap had climbed a ladder to examine the folds of the plastic sheet. “More slack,” someone said. “More folds.” Yavachev had flown in that morning from Abu Dhabi, where he has been working on realizing the duo’s most ambitious work, “The Mastaba,” a tomblike structure made of oil barrels in the desert, which, if completed, would be one of the world’s largest contemporary sculptures by volume. “Inshallah,” Yavachev said. He has been working on it for twenty years, with no end date in sight.

“Jeanne-Claude always used to say we do these projects for ourselves, and if other people enjoy it, that’s a bonus,” he went on. Many of the works were dreamed up decades before they became reality. “The projects find their time,” he said. He recalled a phrase he had learned from Bono, on the roof of the Arc de Triomphe. “Cathedral thinking,” he said. “Cathedral thinking is when you start something that you know that you cannot finish. Any architect of a cathedral, it will take two hundred years to finish a cathedral! You’re never going to see it. It’s very similar.”