On a clear day, you can see forever.

Or sometimes it seems that way.

On a warm Sunday afternoon recently, we hiked along the San Marcos ridgeline trails, starting just west of the Double Peak parking lot (a wonderful place, by the way, to see North County in 360 degrees), stepping around the north side of the hill and down to where the new, big houses are springing up like it was 2005 again.

Then, we trudged up the grade heading toward the hilltop with the radio towers north of San Elijo Hills village. This favorite loop is three miles and holds enough ups and downs to feel like we’re getting some decent work in.

From all along there, the views are quite remarkable.

On this day, it was exceptionally clear. No haze. No smog. Nothing but clear air to the edges of the horizon.

Immediately below to the north are Lake San Marcos and, farther out, the hills of Fallbrook and Camp Pendleton. The collections of roofs and streams of cars on the State Route 78 arterials are reminders that we live in a crowded land, even though we seem to be walking above it all.

To the west is Batiquitos Lagoon and the shimmering sea beyond.

In the distance to the south, the mountains of Mexico’s Coronado Islands; to the northeast, the snow-capped San Bernardino mountains.

East and north, Palomar Mountain sticks out between two humps of the ridges above Valley Center.

The highrises of La Jolla often are on the horizon for those standing in the right place in North County, but I had never noticed (from here) the skyline of downtown San Diego – and the air was so clear on this day that we could make out an airplane coming up from Lindbergh Field and wheeling south across Tijuana before it vanished from view.

And, of course, there is something interesting about watching hot-air balloons rise from the ground below you.

To the west, the outlines of Santa Catalina and San Clemente islands stood distinctly rising out of the sea.

These trails are unique. The paths on this stretch are asphalt so even in wet weather, it’s not a muddy walk.

The city of San Marcos and the San Elijo Hills developers get an “attaboy” for putting them in – and, by and large, agreeing to keep houses below the trail elevations.

But there are curiosities beyond the variety of flora and fauna.

For instance, on the posted “no trespassing” Quartz Street (and its companion Pearl Drive), there are about 10 grand houses sitting empty, looking forlornly out at what must be the grandest view in the county looking west and south.

Ten palaces without tenants.

Who would put up houses only to have them fall into disuse? (By the way, there is a caretaker’s trailer on one of the lots presumably protecting the property from interlopers and vandals.)

The story of these houses and what happened to idle them and leave them empty must be the story of the great housing collapse of recent years – I imagine them tied up in some kind of bankruptcy litigation, owners and lenders and builders all jockeying for the rights.

And what about the fenced gazebo and picnic table area overlooking Lake San Marcos?

We stopped a park ranger and asked about it. He said the site was originally intended for camping, but the fire hazard was too great so it remains cordoned off, unused.

What a memorable place for a birthday party, a place to celebrate on top of our corner of the world.

The only trouble would be lugging the cake and ice cream all the way up and the dirty plates and cups all the way back down.

Kent Davy is the former editor of the daily North County Times. Contact him by email at [email protected].