6″ guns being produced by Bethlehem Steel. Photo: Wikimedia Public Domain, circa 1905

Wikimedia Public Domain
This file was provided to Wikimedia Commons by the National Archives and Records Administration as part of a cooperation project. The National Archives and Records Administration provides images depicting American and global history which are public domain or licensed under a free license.
https://commons.wikimedia.org/wiki/File:Shop_Number_2_annex._6_inch_guns_with_their_mounts_in_foreground,_immediately_in_the_rear,_slides_or_cradles_for_10_inch_-_NARA_-_533708.tif