Frederick Law Olmsted was among the first to raise landscape architecture to a profession and a fine art. He was co-designer of Central Park, head of the first Yosemite commission, leader of the campaign to protect Niagara Falls, designer of the U.S. Capitol Grounds, site planner for the Great White City of the 1893 World’s Columbian Exposition, planner of Boston’s “Emerald Necklace” of green space, and created park systems in many other cities. Olmsted believed a park was both a work of art and a necessity for urban life. Lawrence Hott discusses his documentary "Frederick Law Olmsted: Designing America," about Olmsted’s efforts to preserve nature and create an “environmental ethic” decades before the environmental movement. "Frederick Law Olmsted: Designing America" premieres Friday, June 20, on PBS—it airs at 10:30 on Channel 13 in New York.