The US clothing billionaire Douglas Tompkins has died in a kayaking accident in southern Chile, aged 72.
The North Face and Esprit co-founder died of hypothermia after the kayaks he and five others were in capsized in strong waves, authorities said.
He was taken by helicopter to hospital in Coyhaique but had stopped breathing when he arrived, doctors said.
Mr Tompkins bought up large tracts of land in Chilean and Argentine Patagonia to keep them pristine.
'Legacy of conservation'
A military patrol boat rescued three of the kayakers on General Carrera Lake and a helicopter lifted out the other three, the Chilean army said.
"Doug was a passionate advocate for the environment," said The North Face in a statement. "His legacy of conservation will help ensure that there are outdoor spaces to be explored for generations to come."
On his Chilean land, Mr Tompkins created Pumalin Park, 2,900 sq km (1,120 sq miles) of forest, lakes and fjords stretching from the Andes to the Pacific.
He also became involved in local environmental issues in Chile and Argentina and helped raise environmental awareness there.
In total, he and wife Kris McDivitt Tompkins, the former CEO of outdoor clothing brand Patagonia, are believed to have bought up more than two million acres of land for parks and protected reserves.
Mr Tompkins did, however, at times face heavy criticism from right-wing Chilean politicians who accused him of being part of a conspiracy to grab land in the country.
The North Face was founded in 1964 by Mr Tompkins and a partner in San Francisco, starting out as a "small ski and backpacking retail and mail order operation", according to the company.
A few years later, he helped his then wife Susie Tompkins Buell to start clothing brand Esprit.
Mr Tompkins later sold his stake in Esprit and retired to Chile to use his fortune for environmental causes, founding the Foundation for Deep Ecology with activist Jerry Mander in 1990.
The foundation's website says Mr Tompkins had come to see the consumer culture that his clothing companies had promoted as "another destructive manifestation of an industrial growth economy toxic to nature".