Stone ring at Great Ball Court, Chichen Itza
Credited as "Photograph from the Carnegie Institution"
<p>Carnegie Institution photo, as published in January 1925 "National Geographic" magazine article "Chichen Itza, An Ancient American Mecca" by Sylvanus Griswold Morley. P. 70
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Via archive org at <a rel="nofollow" class="external free" href="https://archive.org/details/nationalgeographic19250101/page/70/mode/2up">https://archive.org/details/nationalgeographic19250101/page/70/mode/2up</a>