By the time we arrived at Termas Los Pozon, the moon shone overhead. But the gatekeeper, sitting in a ramshackle hut, simply accepted our $10 entry fee and waved our car down into the darkness with a nod.
"Park at the bottom of the hill and follow the 100 steps down to the ravine bottom," he said. "You'll see the pools there. We close at 6 a.m."
We had come to Patagonia's lake district -- a vast wilderness punctuated by volcanoes, glacial lakes and waterfalls that divides Chile and Argentina -- to explore the healing power of hot springs, part of indigenous folklore for generations. What we found were a series of spa lodges focused on wellness and pampering, as well as a medicinal centre full of travellers seeking what many consider a hidden "fountain of youth."
Termas Los Pozon, a lakeside ski centre on the outskirts of Pucon, roughly 800 kilometres south of Santiago, Chile's capital, is home to natural hot springs where visitors can bathe in six rock pools under the stars as the icy Liucura river flows by.
To enter the pools, which run along the river's edge, we walked along a dimly lit pathway. Steam rose off the surface of the water, and as we passed ghostly bathers I thought of woodland fairies relishing a primordial celebration of nature. Slipping out of the chilly night air into the 38-degree waters, it was easy to fall under the spell of the hushed surroundings.
Days earlier, we had set off from San Carlos de Bariloche, Argentina's northern Patagonia outpost, for our first stop: the 138-room Termas Puyehue hotel and spa in Chile. Located near a volcano, its open-air aguas calientes have drawn the local Mapuche people for generations -- often with their horses and cattle.
Our guide, Maria Jose Machuca, showed us how locals dig their own thermal pools in the soft banks, scraping away layers of pebbles and mineral clay to expose waters rich in sodium, potassium, calcium and magnesium. "People come to bathe and connect with Puyemama," she said. "That's what they call the spirit of Mother Nature."
There is also a more formal spa in the area. Its thermal pools -- two housed in a solarium lodge and another al fresco -- attract visitors with chronic illnesses or undergoing physiotherapy. As manager Consuela Santana explained, the waters' magnesium is a laxative, sodium lowers blood pressure and lithium acts as an antidepressant. But "the most important quality is the pH balance," she added, "which is very alkaline. When you have a lot of stress, your body gives off acid and the water neutralizes it."
We heeded Santana's warning to soak for only 15 minutes in the piping-hot 40-degree pool before braving the frigid plunge pool. This was a wise move, since the experience left me tingling with a curious awareness of the warm blood coursing through my veins. We then tried the fango spa treatment, which left our skin silky smooth after being exfoliated with mud from the river.
Who knows if it was the heat of the water or its lithium content, but that night I slept like a baby, enveloped in a cocoon of contentedness.
The following morning, we took a lingering drive north to the Termas Huife, set in the Andean forests near the border of Argentina. Here, a handful of lodges with wood-burning stoves, bathtubs that fill with the area's waters and private decks, are a stone's throw from a spa and outdoor pebble-bottom thermal pools.
I tried the suggested therapy for improved circulation -- soaking in the thermals and plunging into the icy river -- but could only take so much of the drastic temperature change. Then I found the outdoor hydrotherapy pool overlooking the river, where spouting cascades of thermal water banished the knots in my shoulders.
