Powerhouse, Hoover Dam, Arizona/Nevada Border
Vintage Postcard via VintagePlum
Look at the group of people down there for scale.
From the seller:
Vintage Postcard: “Hoover (Boulder) Dam Powerhouse - Nevada Wing” — Photo by U. S. Bureau of Reclamation.
Great 1940s “linen” postcard in excellent condition; this card was never posted, and it doesn’t have any writing on the back. Nice colorful vintage interior view of the Hoover Dam Powerhouse, showing the Generators on the Nevada Wing.