There are days and weeks, especially in August, when the heat and the haze and the smog hang heavy over the Central Valley and you can't see the mountains.
But they are there, filtering the air and water of the Valley below, creating weather with their very vastness.
Somewhere up there in the High Sierra, snows are just melting and spring flowers are only now beginning to bloom.
There's a trail up there -- named for famed preservationist John Muir -- that goes from Yosemite Valley to the top of Mount Whitney, passing through canyons and meadows, 13,000-foot crests and granite cliffs.
It's a 211-mile walk on the West Coast's rooftop.
But it's more than a footpath. There are routes in this world that connect more than places. The Orient Express, Route 66, the Appalachian Trail -- all hold the stories of those who went before and the daydreams of those who want to follow.
They hold, in short, the promise of a quest.
"The John Muir Trail has marquee value. People do it at major junctions in their life or at times when they feel the need for a major change, " says Angela Ballard, editor of the Pacific Crest Trail Association's magazine.
Greg High, 55, an Escondido artist who hiked the trail in 2000, approached his trip with apprehension.
"It's a lot to take. The heat, the cold, the exhaustion, no modern conveniences, " he says. "People say to you, 'Gee, why would you want to do that?' And you don't have a good answer until you get back."
Five years after his return, High is still painting what he saw on the trail.
"It's because of the nature of those mountains. I've been to the Alps. I've seen the Pyrenees. But the Sierra Nevada is very special. Muir called them the Range of Light, and they are, " he says.
"Those mountains are something that happens to you. The trail goes over 11 passes, and when you go up and over a pass, you have a really good view of where you're going and where you've been. You see where you'll be in three days and you think, 'How will we ever get over there?' Then you just get back on the trail and one step at a time, you get there.
"To me, that's very metaphoric. If you have a peak, a dream in your future, you need to get going, and keep going, and you'll get there."
The trail, a north-south footpath completed in 1938, opened the High Sierra to the public.
Now the high country faces issues of crowding. The trail has been rerouted several times because portions were worn out by thousands of hiking boots and hooves. The trashing of Mount Whitney, at 14,494 feet the highest peak in the contiguous United States, led to strict permit limits for parts of the trail.
There's a lottery system for Whitney and the Yosemite portion, where most people begin their hike.
When going into the wilderness involves getting in line, how wild can it be?
Larry Fahn, immediate past president of the Sierra Club, says it's important to consider the issue of crowds on the John Muir Trail -- where you might run across four or five people a day -- in the larger context.
"The John Muir Trail has become America's wilderness icon. John Muir frequented the area, and people want to follow his footsteps. It's a very popular trail. But the number of people who will ever see it compared to the general population is infinitesimal, " he says.
Indeed, the number of people who go backpacking is dropping. A 2005 study by the Outdoor Industry Foundation found that overnight backpacking was the one outdoor activity that declined in the previous eight years. Backpacking saw a 22.5% drop that the foundation attributed to people preferring activities that could be done in one day.
"The people who got into backpacking before are getting older, and they don't have the time or their knees can't take it anymore. There's some discouraging trends with young people getting so caught up in their electronic world, " Fahn says.
"But if everyone spent one week in the wilderness, we would have a better country. It rejuvenates and brings about a sense of wonder and possibility and responsibility."
For those who do backpack, and even to some who never have tried it before, the John Muir Trail has taken on the reputation of a modern-day rite of passage.
This summer, the people on the trail will include a group of British soldiers on leave from the war in Iraq, a family moving away from Israel and young couples from Japan. There will be people trying to complete the trail by hiking a one-week section each summer, and Pacific Crest Trail "thru-hikers, " whose longer journey from Canada to Mexico includes all of the John Muir.
Many of the thru-hikers say the John Muir Trail is the highlight of the larger journey.
"It really is the place on the whole Pacific Crest that people most look forward to reaching, " says Ballard, the magazine editor, who made a Pacific Crest Trail journey five years ago.
"When we first hit an elevation of 9,000 feet and I saw my first alpine lake, I was awestruck and I stayed that way for the next two weeks. The granite boulders really do glisten and glow on that mountain, and the sky seems so blue and close."
Ballard says she took the arduous backpacking trip to test herself and her relationship with her boyfriend.
She didn't find out until years later that he carried a ring the whole trip waiting for the time when they weren't too tired or dirty for his proposal.
He had to wait until they got home.
Now they're married and young parents, and sometimes life gets harried.
"We'll just look at each other and say, 'Remember when we lived out of our backpack?' Ballard says. "It brings us back and gives us perspective."
On weekend backpacking trips, Emily Franciskovich, 27, of Visalia, has run into people who were attempting the entirety of the John Muir Trail after losing someone they loved, graduating or getting ready to move.
"It seemed like a lot of people I talked to were doing it after they were coming off of, or going into, something big, " she says.
Last April, Franciskovich -- in the thick of finishing a graduate thesis and working full time -- saw a beautiful backpack on sale. Spur of the moment, she bought it, knowing at that moment that it would mean she would quit her job and this summer finally hike the whole John Muir Trail.
"I've heard about it and dreamed about it for years. But there's so many factors and variables: physical, mental, emotional. Now I just feel prepared for it in so many ways. I've been working full time, going to school. I'm affording myself this luxury, this gift, " she says.
"I'm giving myself the opportunity to just walk."