A major exhibition of paintings and etchings by James McNeill Whistler opens in Washington this weekend—but don't expect to see his mother there.

"An American in London: Whistler and the Thames" spotlights the 19th century American artist's many years in the British capital and his fascination with the storied river than runs through it.

Starting with his vivid depictions of life along the Thames, the show—at the Smithsonian's Freer and Sackler Galleries on the National Mall—progresses to the moody, virtually abstract twilight images, or Nocturnes, that Whistler began creating around 1871.