This photo was taken during construction of the grounds for the 1909 World's Fair held in Seattle, the Alaska Yukon Pacific Exposition. It was probably taken by the official photographer, Frank Nowell. Otto apparently printed it on contract for the American Post Card Co.
There is also an Image 36 (36 - F.O.E. Parade 8/13/08 Bremerton in Foreground). Reuse of image numbers and different image series make it difficult to know how many images Otto published.