The Panama Canal, The Invisible Wonder of the World is a pictorial history of the major United States construction era of the Panama Canal (1907 - 1914.)
The purpose of the book is to show the hidden effort that went into the canal - an effort that is today hidden from the view or passengers transiting the canal and locks. Authors of the era knew that it would be a challenge for future travelers to appreciate the scope of this project:
"The busy scenes still prevailing in the canal zone will now soon have disappeared like a dream, and the future traveler who looks from the ship-rail over the shining waters of Gatun Lake or beyond to the vast and silent tropical forest will have difficulty in reconstructing the spectacle which the narrow lands presented during the ten strenuous years of construction." J. Saxon Mills, "The Panama Canal, A history and description of the enterprise." 1913.