As my horse, Sorpresa, rounds the corner, he picks up his pace even more. Galloping at breakneck speed on a path barely wider than my saddle, he negotiates the dusty ochre-hued canyon with the skill and grace of a beast not only used to this terrifying terrain, but also of one that is doing so with great relish.

If I have to admit it, so am I. Even when we stop at a ledge and I look down a vertiginous, almost sheer drop, I remind myself this is what these horses are bred for.

As his ears prick forward, I lean far back, and Sorpresa plunges down into the sandy drop with three big leaps and then gallops forward onto the cactus-strewn open plain; I feel straight out of the 1962 film 'Lawrence of Arabia.'

This is the third day into my 10-day adventure in Chile, which will take me from the arid red-earthed Atacama -- one of the driest terrains on the planet -- down to the breathtaking mountains, glacial lakes and never-ending skies of Patagonia.

Staying at Explora lodges, an all-inclusive adventure trip operator that organizes all meals and each day's activities for you, I have opted for a mixture of hiking and riding in both locations. Having spent much of my early life on a horse, I stopped at 14 after breaking my collar bone. But I had been itching to get back in the saddle again.

One thing I didn't account for, however, was that this so-called most arid place on the earth was going to be experiencing its worst rains in years. I had gone in February during Chilean summer. While Atacama is usually perfect year around, Patagonia is best during November to March, so I wanted to catch this season. Normally, the amount of rain wouldn't be a problem. But the hardened earth's inability to soak up the rainfall quickly resulted in flash floods, limiting our choice of walks.

On the first day, I join a small group of six, including lawyers from New York and retired teachers from Germany. As I am on my own, I quickly get adopted by the more friendly couples, and the walk is punctuated by jolly conversation.

We pass over red earth, rocky hillocks and through low-lying ravines. This isn't an arduous hike but one to introduce us to the land. After three hours, it culminates with sundowners of delicious local Cabernet Sauvignon by the jeep, while watching a spectacular double rainbow, one blessing of the inopportune weather.

Dinners are delicious and utilize as much local fare as possible. After a meeting with the guides on the next day's activities, I feast on river trout with fresh peas and fall quickly into a deep slumber in my simple but comfortable room.

The next day is more educational, with a tour around the Cuchabrache in the Catarpe Valley, where the 3,500-year-old petroglyphs depict llamas and jaunty deer, all facing the direction of where water is to be found. We are also introduced to some of the local plants, exotic cure-alls, such as the delightfully named Rica Rica (for stomach problems), Chilca (for bruises and muscular pains) and Pingo Pingo (for relaxation), as well as cocoa, the staple local high.

On day three, I head off into San Pedro de Atacama, a charming town with simple whitewashed adobe houses lining the streets and a pretty square where gaggles of travelers and hippies strum on guitars and smoke around plastic tables. The afternoon is spent with my trusty steed, Sorpresa, whose energetic gait means an early evening bath in the outdoor hot tub with a glass of sparkling Chilean white; it instantly eases the pains.

The next day, I embark on the most testing walk of the trip so far. In search of a challenge, I ask the guide to recommend the most arduous walk: Rio Grande -- Machuca is a long, 4 1/2 to 5 1/2 hour trek downhill. Having met up with my fellow walkers, two fit Russians, at the lodge, we ask to do the trek uphill instead of downhill. The fun starts when our guide makes the three of us wade waist-deep through some rapids, shoes and bags on heads. Under a fine blanket of rain, we heave ourselves up slope after slope, the valley disappearing in fog.

We come to the abandoned village of Penaliri, where lunch is a pitstop in a former shepherd's house and the sandwiches, brownies and mate tea provided by our guide come as a welcome relief. We set off for the final slog. As we round a corner and leap from island to island of rushes, trying to avoid the icy water, we come across a herd of llamas feasting contentedly on grass. They are adorned with brightly colored rags, draped around their fluffy necks their by farmers to give their thanks to the gods for their livestock.

Our last stretch of this difficult walk is a final push up a steep hill. As we rise to an altitude of 3,930 meters, breathing becomes harder. Just when I think I am about to collapse, we turn the final corner and a flock of pink flamingos takes flight. My feet are soaking and I can barely feel my limbs, but the sense of achievement is immense.

Next stop, via a night in the hip W hotel in Santiago, is a four-hour flight to Patagonia. I am told by a friend to request to sit at a window seat on the left, and an hour or so into the flight I see why -- the most spectacular view of the sun-kissed Andes and piercing blue glacial lakes below.

I arrive and it is a three-hour drive to the lodge in the Torres del Paine National Park, set amid a dramaticlandscape -- towering snow-capped mountains, bright-blue lakes and lush grass; I sit outside for an hour or so taking in the changing shapes and colors as the day ends.

I opt for two major walks and one ride. My first walk, the Grey Glacier, is one of the most popular. This walk is stunning, climbing slowly up a winding mountain path until more of this vast landscape is revealed. Eventually, we climb over the brow of the craggy hill and the glistening glacier is in front of us, as well as other trekker groups admiring the view. And just as I am sitting down to a warming drink of coffee and Baileys to wash down my beef sandwiches, I do a double take as I spot my neighbors from London. The coincidence of this is almost too much to comprehend as we are literally at the end of the earth.