An abstract painting of intersecting lines of color has been hanging upside down in various galleries for 75 years, an art historian found. The 1941 work by Dutch artist Piet Mondrian, titled New York City I, was first displayed in New York’s MoMA in 1945, but has been displayed in the collection of the German federal state of North Rhine-Westphalia in Düsseldorf since 1980. It’s currently displayed with its multicolored lines thickening at the bottom of the piece, but curator Susanne Meyer-Büser realized that was a mistake earlier this year when she started researching for the museum’s new show on Mondrian. “The thickening of the grid should be at the top, like a dark sky,” Meyer-Brüser said. “Once I pointed it out to the other curators, we realized it was very obvious. I am 100 percent certain the picture is the wrong way around.” The curator added that the adhesive tapes on the artwork are already “hanging by a thread,” meaning it’s now too risky to hang the painting the right way up.