Coolidge Dam.
Almost all the photos taken on the entire three month trip were only of family, with the exception of the dam.
"The Coolidge Dam has just been finished and was dedicated Mar 4, 1930 by Calvin Coolidge. It is 920 feet long counting 2 spillways 250 ft high from bed rock, and has a capacity of 1,200,000 acre feet. It dams up the Gila River."

Thank you for looking.