1842-1894 1879-1975 20thcentury appalachaintrail benton centuryofprogressinternationalexposition centuryofprogressinternationalexposition(1933-1934:chicago drama eminentdomain environmentalconservation environmentalism environmentalpolicy general history impresarios inventors local nature natureconservation politicalaspects protection publicuse south state steele trails travel unitedstates world'scolumbianexposition world'scolumbianexposition(1893:chicago