Georgia O'Keeffe's first solo exhibition was held at 291, the New York gallery founded and run by Alfred Stieglitz. The exhibition opened in 1917 and helped introduce her abstract drawings to a wider art audience.
The gallery's formal address was 291 Fifth Avenue, which gave it the name by which it became famous. Stieglitz used the space to present pioneering modern art and photography, including works by European artists and emerging Americans.
O'Keeffe's 1917 show followed Stieglitz's discovery of her charcoal abstractions. The relationship with the gallery became a major step in her professional career, although her later work expanded far beyond the early abstract drawings shown there.
A common mix-up is to call the event an Armory Show. The Armory Show was a major 1913 exhibition at different venues; O'Keeffe's first solo exhibition was specifically at 291 in 1917.