"OH yes. He knows we're here," our naturalist Pete says, in answer to my naive question, as I gawk at a black bear ripping apart a fallen cedar.

He's only yards from our hiking group in California's Yosemite National Park.

Huge paws with very noticeable claws, effortlessly tear thick shards of bark off the tree trunk. I can't help but consider if my torso would put up any more resistance if he charged at us.

In reality though, the bear would more likely flee in fear and probably climb a tree, than attack, Pete reassuringly explains.

Rangers estimate 300-500 brown bears can be found in America's oldest government park, which celebrates its 125th anniversary next month. They'll often encroach on camp grounds in search of food and regularly wind up in humane bear traps dotted around the park, giving rangers the chance measure and examine them, before releasing them in less busy areas.

But as I peer through a bush, desperately trying to focus my camera for that one brilliant shot, I feel remarkably alone, sharing the fleeting experience with nothing but nature itself.

That is, I came to realise, one of the real assets of Yosemite. For a park that sees an estimated 3.7 million visitors a year, most of which spend all their time in Yosemite Valley occupying only one per cent of the park, it's remarkably easy to find tranquillity.

We continue our walk, a hike from the visitor's centre in the valley to Mirror Lake, at the base of Half Dome, a granite peak rising 4,800 feet above the ground. It's a popular ascent for amateur rock climbers, who can trek up the back face, using ropes and chains permanently in place.

I can only imagine the view from the top is as spectacular as it is from the bottom, when I see the mountain's reflection in the still water. Awestruck at the beauty before us, we sit in silence until our guide encourages us to read a selection of quotes from Scottish-born naturalist John Muir, who was writing about the park 140 years before I arrived.

"I only went out for a walk, and finally concluded to stay out till sundown. For going out, I found, was really going in," Muir wrote, in the years Yosemite was his muse.

It's true, the park does draw you in and it had taken our small group around an hour to walk only two miles, taking in scenery, marvelling at the sky-scraping cedars and sequoias, and spotting the native fauna.

The open air train tour is also a popular option for day trippers to the park, who wish to see the main sights in a short period.

I've never really taken to sightseeing buses, but our 'train' is more than that. Sarah, our guide, is as passionate as any other ranger in the park, and a wealth of information cascades over us as we pass across the valley floor.

After a few short photo stops, we arrive at the ultimate view in Yosemite, opposite Wawona Tunnel, the first vista most visitors see as they arrive at the park.

We can see across the entire valley, spotting the mountains El Capitan and Half Dome, Dana Meadows and several seasonal waterfalls, all of which are being captured on cameras, phones and video around me.

The advance of technology to record the moment amuses me, when I consider how 150 years ago, when Abraham Lincoln signed the Yosemite Grant Act, designating the region to be preserved for its natural beauty and for public use, the only thing visitors would take away then, were their memories.

Basingstoke Gazette:

That legislation paved the way for Yellowstone to become the country's first federal park a few years later, and the establishment of America's National Park program as it's known today. Yosemite joined the rest after President Teddy Roosevelt spent a few nights in it at Muir's invitation, and fell in love with it.

With visitors in the millions now, great efforts are being made to preserve the region, with almost 90% of the park now designated as wilderness. Artificial inducements to visit the park have also been curtailed, such as the nightly 'firefall', where glowing embers were pushed off a cliff face to create an admittedly spectacular waterfall of fire.

Our night, however, is spent sitting under the wide open sky, competitively watching for shooting stars.

It would be easy to spend weeks exploring this magical corner of California and get lost in its grandeur as Muir once did. However, it would be unthinkable to visit America's sunny west coast without sampling some of its world class wines.

So my Trafalgar tour winds its way to Sonoma county, next to the well-known Napa Valley, where the wine is equally as exquisite, for a lesson in blending a fine red. I'll happily admit, I'm no connoisseur, but I'm intrigued by the scientific approach we're taught, to develop our own formula at Ravenswood Winery's warehouse.

Basingstoke Gazette:

Eight units of Petite Sirah, four units of Cabernet and eight units of Zinfandel, seems a pretty good mix to me.

Our tour leader blesses us with a leisurely start the following morning, after which we drive to the town of Sonoma to prepare lunch at Ramekins Culinary School. I had marked this event as one of the highlights of our escorted tour and soon find myself heavily invested in a New York-style cheesecake.

A pair of patient chefs guide our group through preparations for each course, for what ends up being a delicious meal ahead of our short drive to San Francisco.

I find myself bounding around our coach with youthful enthusiasm as we approach the Golden Gate bridge from the north, which is as impressive as I had always imagined.

We step out of our coach to stroll across, taking in the spectacular views across San Francisco Bay, the city's skyline and the infamous Alcatraz Island.

Back in the coach, we head to Chinatown, the hip Mission and Castro districts, and Haight-Ashbury - the centre of the Summer of Love movement in the late 1960s.

Thousands of young Americans crashed in ageing Victorian houses in that suburb, to share peace, love and a few illicit substances, in what is now regarded as a grand social experiment.

And while the area has changed significantly in the last 45 years, the friendly spirit remains across San Francisco. In a one-block stretch, I'm stopped for a hug, asked where I'm from and given the chance to take a photo of some locals posing in front of one of the city's well crafted murals.

But my thoughts drift back to Yosemite, where it's easy to imagine that nothing has changed in centuries and, like Muir, I hope it never will.

To paraphrase the Scotsman, "The mountains are calling and you must go."

TRAVEL FACTS

Nick McAvaney was a guest of Trafalgar (www.trafalgar.com/uk; 0800 533 5617) and United Airlines (www.united.com).

Trafalgar's eight-day Northern California itinerary costs from £2,730 per person, including seven nights' B&B accommodation, a Highlight Dinner with wine in Napa Valley, and four evening meals, including a Be My Guest dinner at Happy Girl in Monterey, VIP door-to-door private airport transfers, sightseeing and the services of a professional Travel Director throughout.

Trafalgar's eight-day San Francisco & Wine Country Delights itinerary costs from £2,855 per person, including seven nights' B&B accommodation, a picnic lunch with drinks at a winery in St. Helena, and four evening meals, including a Be My Guest dinner at Sonoma Valley, VIP door-to-door private airport transfers, sightseeing and the services of a professional Travel Director throughout.

For more information on the destination, visit www.DiscoverAmerica.com