Helen Frankenthaler’s first professionally exhibited work—and her best known—was Mountains and Sea (1952), a soak-stain painting she completed after a road trip when she was just 23 years old. Frankenthaler pioneered that particular technique. She thinned oil paint with turpentine and poured it on an unprimed canvas, creating feathery pools of color. Frankenthaler had traveled to Nova Scotia, and its rugged beauty stuck with her. She would go on to produce many more landscapes of feeling, but was never credited with her invention. This exhibition, her largest in Europe and her first institutional show in Switzerland, gives the modernist her due. —Elena Clavarino