Black and white image of Secretary of the Interior, Dr. Ray Lyman Wilbur, on a tour of inspection at Hoover Dam. It was under Dr. Wilbur's supervision that the Boulder Canyon Project was commenced. In the background the concrete form used in lining the 50-foot diversion tunnels at the outlet portal of Diversion Tunnel No. 2 can be seen. Note: Boulder Dam was officially renamed Hoover Dam in 1947.