In a ceremony on the edge of South America’s famed Pumalín Park, Chilean president Michelle Bachelet and the American philanthropist Kristine Tompkins today pledged to expand Chile’s national parkland by 10 million acres. In what has been billed as the world’s largest donation of privately held land, Tompkins—the founder, with her late husband, Doug Tompkins, of Tompkins Conservation—plans to hand over to the government slightly more than a million acres. The Chilean government, for its part, will contribute nearly 9 million acres of federally-owned land.

Kristine Tompkins—a California native who served as the CEO of the clothing company Patagonia before marrying Doug Tompkins, a founder of The North Face and Esprit clothing companies—spent more than two decades acquiring the land and