Nature was idealized in the nineteenth century. The Romanticists communed with nature to experience God, and the New England Transcendentalists went even further in venerating nature. In this era when nature was valued in an almost religious sense, public parks multiplied.
The landscape design genius Frederick Law Olmsted carried out these popular ideals on the grandest possible scale. After designing Central Park, he was frustrated in his desire to build a regional open-space network throughout New York City. Boston welcomed him. In 1869 he began advising the city on a comprehensive park system. During the next decade he focused on the Arnold Arboretum, Back Bay’s Charlesgate, and the Fens. In 1887 he created his plan for an interconnected park system for Boston that would stretch from the Common to Franklin Park, passing through many Boston neighborhoods. Beyond this, he designed a number of other parks and initiated a metropolitan open-space plan.
Albert Fein observed, “Olmsted’s record of achievement in Boston after his defeat in New York City was owing to the social and political support he found there. Boston, unlike New York, still retained an effective intellectual and social elite committed to large-scale environmental planning.” Olmsted’s network of Boston parks remains the largest continuous green space through an urban center in the United States.
Upon Olmsted's retirement in 1895, his sons continued the practice as the Olmsted Brothers, and designed park systems across the U.S. and Canada. They became founding members of the American Society of Landscape Architects, and were active in the creation of the National Park Service, for which they provided plans for Acadia and Yosemite.
By James Notman, Boston; engraving of image later published in Century Magazine (source) - The World's Work, 1903: http://archive.org/stream/worldswork06gard#page/3938/mode/2up, Public Domain, https://commons.wikimedia.org/w/index.php?curid=26824311