Agricultural Building, Alaska-Yukon-Pacific Exposition, Seattle, Washington. Caption says "Portion of the Formal Gardens." Formal garden in foreground. Behind that at right is the low fence around the pool known during the Exposition as Geyser Basin / Arctic Circle (now Drumheller Fountain). In the distance at right is the U.S. Government Building. <br>
The copyright on the image is dated 1908, so this is presumably before the Exposition. This looks like it is at least retouched; it is definitely a photo rather than an architectural drawing, though, because Nowell was a photographer.
<bdi><a href="https://en.wikipedia.org/wiki/en:Frank_Hamilton_Nowell" class="extiw" title="w:en:Frank Hamilton Nowell"><span title="American photographer and postcard publisher">Frank H. Nowell</span></a>
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Edition dated 1909-02-20. Photo copyrighted 1908.
<p><i>The Argus</i> Alaska-Yukon-Pacific Exposition special issue, p. 11. 
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Photographed digitally from a copy in the Seattle Room at the downtown Seattle Public Library, then cleaned with GIMP.