Ralph Waldo Emerson — American writer Ralph Waldo Emerson in 1857
Photo Credit: Public Domain, https://commons.wikimedia.org/w/index.php?curid=11868430

Harvard's Hollis Hall in 1934 — Thoreau's dorm, it was built in 1763 by Thomas Dawes, and housed George Washington's troops during the American Revolution
Photo Credit: By Arthur C. Haskell, photographer. - Public Domain, https://commons.wikimedia.org/w/index.php?curid=9599966

Harvard Yard — Freshman dormitories
Photo Credit: By The original uploader was Mancala at English Wikipedia. - Transferred from en.wikipedia to Commons by Vinhtantran. Created by user:Mancala., Public Domain, https://commons.wikimedia.org/w/index.php?curid=5922104

Walden — Cover art from first edition of Henry David Thoreau's Walden (1854)
Photo Credit: By Unknown -Public Domain, https://commons.wikimedia.org/w/index.php?curid=2226804

Edward Stratemeyer —
Photo Credit: By Unknown - http://www.keeline.com/Stratemeyer/WC_TOC.htm, Public Domain, https://commons.wikimedia.org/w/index.php?curid=10939714

Cover of The Tower Treasure —
Photo Credit: By Source, Fair use, https://en.wikipedia.org/w/index.php?curid=22318243

Devil's Rock — Overlooking Lake Temiskaming, near Haileybury, likely inspired descriptions in The House on the Cliff
Photo Credit: By Jean-Paul Lefaivre, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=46645484

Main Street, Haileybury, 1915. — Town where McFarland grew up, it serves as a model for the Hardy Boys' Bayport
Photo Credit: By Unknown - http://www.museevirtuel-virtualmuseum.ca/sgc-cms/histoires_de_chez_nous-community_memories/pm_v2.php?id=record_detail&fl=0&lg=English&ex=00000444&rd=113500#, Public Domain, https://commons.wikimedia.org/w/index.php?curid=33075135

Charles Leslie McFarlane — Original ghost-writer who used the name Franklin W. Dixon
Photo Credit: https://www.northernontario.travel/northeastern-ontario/charles-leslie-mcfarlane-origins-of-the-hardy-boys-novels

Hawk-eye attacks Magua — Illustration from 1896 edition of The Last of the Mohicans, by F.T. Merrill. The drawing occurs when Hawk-eye attacks Magua in the cave where Alice is held captive. The Last of the Mohicans, J. Fenimore Cooper, 1896.
Photo Credit: By Frank T Merrill - Public Domain, https://commons.wikimedia.org/w/index.php?curid=9058702

James Fenimore Cooper — Photograph by Mathew Brady, 1850
Photo Credit: Public Domain, https://commons.wikimedia.org/w/index.php?curid=836134