Each of the training camps had drill fields called “grinders” where the recruits marched. The huge regimental drill hall in the background of the top photo allowed training during all kinds of weather. They were billed as the largest clear span (without posts) structures in the world at that time. The structure in the top picture is probably the drill hall at Camp Bennion.
At least two of the drill halls found life after the Navy. One found a new usein Spokane for many years as a Costco. It is still there, just off the Division street exit, and now houses a Goodwill warehouse.
Another of the drill halls was donated to the University of Denver, disassembled, and reassembled on the DU campus in 1948-49. It was used as a hockey arena that fans called “the old barn.” It stood on campus for nearly 50 years.