Patagonia, Chile: Superb hiking and wildlife in Chile's new national park

Seven hundred and twenty-five kilometres of fencing doesn't sound like that much, until you have to pull it all down. Until you have to roll up 725km of barbed wire and drag it away; until you have to pull up tens of thousands of fence posts and dispose of them somewhere, it probably doesn't sound like that much at all.

But Kristine Tompkins knows how much it is. The environmentalist, philanthropist and former chief executive of the Patagonia clothing brand faced just such a task when she and her late husband, Doug Tompkins, bought Estancia Valle Chacabuco, a huge tract of land in the northern part of Chilean Patagonia, in 2004. The pair dreamed of returning the sheep farm to its former glory, of bringing back the native animals, regenerating the grasslands, and eventually donating the entire thing to the Chilean government to become a national park.

To begin doing that, however, they had to sell all the sheep, and tear down all the fences.

"When we bought [the farm] there were 25,000 sheep and it was lambing season, so within six weeks there were about 50,000 sheep," Kristine says, sipping a coffee in the lodge at what is now Parque Patagonia, the beginnings of that national park. "We actually wanted to start on the other side of the border [in Argentina]. But when this estancia came up for sale we thought, God almighty, this would be an extraordinary, once-in-a-lifetime conservation opportunity."

The fruits of Kristine and Doug's labour are laid out before us today. Outside the window of this lodge lies one spectacular part of the world, a series of grass-covered mountains that personifies the landscape of northern Patagonia, a rugged, 80,000-hectare reserve where huemuls (native deer) and guanacos (Chilean animals similar to llamas) once again roam free.

It's a stunningly ambitious and ultimately successful conservation project, part of Kristine's grand plan to rid northern Patagonia of destructive farming and return the mountains, the lakes, the rivers and the rocky outcrops to nature, and to the Chilean people. And today, it turns out, is a momentous day.

Later this morning, the official handover of Kristine's land to the Chilean government will be completed. It will be the largest gift of its kind in history, and the beginning of what will eventually become a huge, emblematic national park, bigger than Torres del Paine further south, when Parque Patagonia is joined up with the nearby Jeinimeni and Tamango reserves.