Glen Canyon, a section of the rockface formations. Todd Webb printed most of O'Keeffe's contact sheets and photographic prints. This photograph is from the Glen Canyon album that Todd Webb gave to Georgia O'Keeffe "In memory of the great August 1961 trip down the Colorado River."

Closeup of a section of a rockface formation. Todd Webb printed most of O'Keeffe's contact sheets and photographic prints. This photograph is from the Glen Canyon album that Todd Webb gave to Georgia O'Keeffe "In memory of the great August 1961 trip down the Colorado River."

Closeup of a section of the rockface formations. Todd Webb printed most of O'Keeffe's contact sheets and photographic prints. This photograph is from the Glen Canyon album that Todd Webb gave to Georgia O'Keeffe "In memory of the great August 1961 trip down the Colorado River."

Closeup of a section of the rockface. Todd Webb printed most of O'Keeffe's contact sheets and photographic prints. This photograph is from the Glen Canyon album that Todd Webb gave to Georgia O'Keeffe "In memory of the great August 1961 trip down the Colorado River."

View of a section of the rockface formations in the canyon with shadows. Todd Webb printed most of O'Keeffe's contact sheets and photographic prints. This photograph is from the Glen Canyon album that Todd Webb gave to Georgia O'Keeffe "In memory of the great August 1961 trip down the Colorado River."

Section of the rockface along the river. Todd Webb printed most of O'Keeffe's contact sheets and photographic prints. This photograph is from the Glen Canyon album that Todd Webb gave to Georgia O'Keeffe "In memory of the great August 1961 trip down the Colorado River."

Closeup section of the rockface. Todd Webb printed most of O'Keeffe's contact sheets and photographic prints. This photograph is from the Glen Canyon album that Todd Webb gave to Georgia O'Keeffe "In memory of the great August 1961 trip down the Colorado River."

Closeup of a section of the rockface. Todd Webb printed most of O'Keeffe's contact sheets and photographic prints. This photograph is from the Glen Canyon album that Todd Webb gave to Georgia O'Keeffe "In memory of the great August 1961 trip down the Colorado River."

View of sections of the rockface along the Colorado River. Todd Webb printed most of O'Keeffe's contact sheets and photographic prints. This photograph is from the Glen Canyon album that Todd Webb gave to Georgia O'Keeffe "In memory of the great August 1961 trip down the Colorado River."

Closeup of a section of the rockface formations. Todd Webb printed most of O'Keeffe's contact sheets and photographic prints. This photograph is from the Glen Canyon album that Todd Webb gave to Georgia O'Keeffe "In memory of the great August 1961 trip down the Colorado River."