1912 Bird's-eye view of the Panama Canal by Gilbert Hovey Grosvenor, National Geographic Society (US), from the Digital Commonwealth - commonwealth 9s1619499. (<a rel="nofollow" class="external free" href="https://www.digitalcommonwealth.org/search/commonwealth:9s1619499">https://www.digitalcommonwealth.org/search/commonwealth:9s1619499</a>)
Gilbert Hovey Grosvenor, National Geographic Society (US)
Digital Commonwealth