Chile has officially designated a national park network including land privately donated by a US couple.
The government signed a deal with Kristine McDivitt Tompkins, who worked with late husband Doug for decades to protect areas of Patagonia.
Mr Tompkins, founder of the North Face clothing label, died in a kayaking accident in Chile in 2015.
Chilean President Michelle Bachelet called the signing an "unprecedented preservation effort".
Tompkins Conservation, the not-for-profit organisation set up by the couple, said the area being protected was roughly the size of Switzerland.
Their donation is thought to be the largest of land by private owners to a country.
The move will create five new national parks, and expand three others. In total it adds about 10 million acres of land, about one tenth of which was donated by the Tompkins.
The Chilean government wants the string of national parks to span a tourist route of more than 1,500 miles (2,400km) across the country.
Mrs Tompkins was formerly the CEO of outdoor brand Patagonia, and her husband was one of the founders of outdoor brands The North Face and Espirit.
They relocated to Chile in 1994 to work on conservation, buying up land to ecologically preserve as wilderness.
Their motives were viewed with suspicion locally, and right-wing Chilean politicians accused the US couple of land grabbing.
Kristine Tompkins signed an agreement with the national government in March 2017, following her husband's accidental death.
"I am proud of my husband Doug and his vision which continues to guide us, in addition to our entire team, for completing these two national parks and the broader network, a major milestone of our first 25 years of work," she said.
Monday's designation was the latest act of natural protection by the outgoing Chilean President Michelle Bachelet.
In 2017 an area off the coast of Easter Island was designated as one of the world's largest marine protection zones.