What was Georgia O'Keeffe's first major New York subject series?

Georgia O'Keeffe's first major New York subject series depicted New York skyscrapers. She began making city paintings after moving to New York in the early 1920s, focusing on buildings such as the Shelton Hotel.

These works were significant because skyscrapers represented a distinctly modern American subject. O'Keeffe transformed architectural forms into simplified arrangements of verticals, curves, windows, and blocks of color rather than treating them as ordinary city views.

Her New York paintings predate her best-known New Mexico landscapes and flower studies. The series is also separate from her later abstractions, although O'Keeffe continued to move between recognizable subjects and nonrepresentational forms throughout her career.