Public domain
Shasta Dam, Shasta County, California. Vibrating newly-poured concrete at the dam to remove excess air and assure even settling
From the collection of Library of Congress. Free to download, adapt and use — no permission needed.
Credit lineShasta Dam, Shasta County, California. Vibrating newly-poured concrete at the dam to remove excess air and assure even settling. 1942-01-01. Lee, Russell. Farm Security Administration/Office of War Information Collection, Library of Congress. Public domain.