Americans have always been drawn to Paris, but Yankee artists of the late 19th century were transformed by it. "Americans in Paris 1860–1900," a new exhibition at London's National Gallery (www.nationalgallery.org.uk; February 22–May 21), showcases the city as muse through more than 100 paintings by U.S. expats. On display are John Singer Sargent's now-iconic Portrait of Madame X (1884), so fiercely criticized in its day that the artist later left Paris for London; James Abbott McNeill Whistler's White Girl (1862), which had a controversial showing at the notorious Salon des Refusés in 1863; and works by lesser-known Francophiles like African-American Henry Ossawa Tanner. Women are estimated to have made up a third of the American art students in Paris during that period, and the attention they receive in the exhibition—with particular emphasis on Mary Cassatt, the only American to show with the French Impressionists—is revelatory.