(CNN) -- When discussing his favorite images from the "Greatest
Photographs of the American West" traveling photography exhibit,
National Museum of Wildlife Art president James McNutt, who
curated the exhibit, starts with the oldest: William Henry
Jackson's "Mountain of the Holy Cross." Taken in Colorado on
August 24, 1873, the photograph would become as legendary as the
mountain itself -- not for the effort it took to get the
picture, but for what it signified to a country healing from the
Civil War and pushing ever westward. Hauling hundreds of pounds
of photo equipment up to a vantage point on an opposite ridge to
capture snow-filled crevasses that created a perfect vertical
cross on the mountain face, Jackson produced an image that,
according to McNutt's introduction in the exhibit's companion
book, came to symbolize "the union of America, Nature and God
that fulfilled a romantic destiny." Jackson's famous shot became
one of the country's favorite photographs of the 19th century
and effectively introduced