On a visit delayed by a long stretch of rain the day before, Venue drove east from downtown Los Angeles to visit the Puente Hills landfill--the nation's largest active municipal dump--near the city of Whittier.

An astonishing and monumental act of landform construction, Puente Hills is scheduled to close in October 2013, to be replaced by the much larger and geographically far more remote Mesquite Regional Landfill, two-hundred miles southeast in the Imperial Valley.

As we approached the site, the scale of the landfill became more clear, and the rhythm of its expansion was also evident in the traffic all around us, as dump trucks bumped and rumbled down the highway off-ramp, all on their way to add mass to the trash mountain looming on the right side of the freeway, blocking the sun.

At the entrance to the dump sits the unassuming two-story headquarters of the Los Angeles County Sanitation Districts. Basil Hewitt, a public information officer, met us there to escort us up the mountain in his minivan.

Over the next few hours, Hewitt patiently answered our many questions about the site's history, its design, and its impending closure, while good-humoredly tolerating our recurring expressions of awe at just how unearthly a place Puente Hills can be.

The landfill opened in 1957, and was taken over by the Sanitation Districts in 1970. It sits on a 1,365 site, half of which is devoted to a buffer zone and wildlife preserve, leaving an area roughly the size of New York City's Central Park to receive one third of Los Angeles County's trash.

Over the past three decades, Hewitt told us, Puente Hills has received nearly 130 million tons of garbage. As Edward Hume writes in his excellent book, Garbology: Our Dirty Love Affair with Trash, this is a hard quantity to visualize. He offers the following analogies to convey its truly monumental scale:

Here's one way to picture it: If Puente Hills were an elephant burial ground, its tonnage would represent about 15 million deceased pachyderms--equivalent to every living elephant on earth, times twenty. If it were an automobile burial ground, it could hold every car produced in America for the past fifteen years.

What began as a small municipal dump, filling in a canyon on the edge of the San Gabriel Valley (acting literally as "landfill") has turned, over four decades, into a mountain-building exercise.

Hewitt told us that Puente Hills now rises to the height of a forty-story building, meaning, as Hume notes, that if the landfill was a high-rise, "it would be among the twenty tallest skyscrapers in Los Angeles, beating out the MGM Tower, Fox Plaza, and Los Angeles City Hall."

For quite some time, the garbage mountain of Puente Hills has been rising above its surrounding terrain, resembling nothing more than a huge and eerily modern version of an ancient tell--those giant mounds in the Middle Eastern deserts that mark where once-might cities rose and fell, and that now lie bured and broken beneath the sands.

We headed upward in the minivan, stopping to learn how the weigh station worked. Pulled over, we watched as trucks rolled up, paused on the gigantic scale (Puente Hills currently charges $38 a ton), then coughed and belched their way further up the hillside.

As he started the minivan back up, Hewitt made the fascinating observation that just a few years ago, this line of trucks would have been significantly longer, backed up sometimes all the way to freeway off-ramp. Toward the end of 2007, all of a sudden, Hewitt told us, "Puente Hills was like a ghost town. People who had worked here for forty years had never seen anything like it."

From a peak of 1,900 trucks per day in summer 2007, thirty or forty of which would be loaded with construction debris, Puente Hills' traffic decreased to only 400 trucks a day by the end of the year. "When it first happened, we didn't know what the heck was going on," Hewitt explained. "We're not economists, but, in retrospect, we figured out something was up in December 2007, and all those banks didn't start to fail until fall 2008."