This is one of the exhibit halls at the 1909 World's Fair held in Seattle, the Alaska Yukon Pacific Exposition. The photo appears to have been taken during construction of the grounds, in which case it would be a Frank Nowell photograph. Only Frank Nowell and his staff were allowed to take photos during construction. Otto apparently printed this image on contract for Central News Co.
There are three other images numbered 8:
Reuse of image numbers and different image series make it difficult to know how many images Otto published.