<p>From the materials for the <a href="https://en.wikipedia.org/wiki/Alaska-Yukon-Pacific_Exposition" class="extiw" title="en:Alaska-Yukon-Pacific Exposition">Alaska-Yukon-Pacific Exposition</a> of 1909, held in Seattle.
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Three photos, collectively entitled "Children's playgrounds". These are all Seattle Parks. The bottom one is the Lincoln Playfield, now Cal Anderson Park on Capitol Hill.
Webster and Stevens. Scanned by the Seattle Public Library.
<i>The Argus</i> Alaska-Yukon-Pacific Exposition special issue, p. 21. <a rel="nofollow" class="external autonumber" href="http://cdm200301.cdmhost.com/cdm4/browse.php">[1]</a> (see filename for exact location)