The newborn world liquefied under pummeling asteroid impacts. Heavy elements sank, generating still more heat, and a dowry of radioactive atoms kept the planet’s interior warm even after the surface cooled and hardened.

Eventually, the inmost core crystallized under intense pressure, but the next layer remained a swirling metal fluid, a vast electric dynamo. Higher still congealed a mantle of semisolid minerals—superdense pyroxenes and olivines and lighter melts that squeezed up crustal cracks to spill forth from blazing volcanoes.

Heat drove the circulating convection cells, jostled the plates, drove the fields. Heat built continents and made the Earth throb.

Heat also kept some water molten at the surface. Preorganic vapors sloshed in solution, under lightning and fierce sunbeams.…

The process started taking on a life of its own.

A range of minor mountains divides the city of Los Angeles. During the city’s carefree youth, great battalions of trucks streamed toward the little valleys between those hills, brimming with kilotons of urban garbage.

Coffee grounds and melon rinds, cereal boxes and disposable trays …

In those profligate times every purchased commodity seemed to come inside its own weight of packing material. The average family generated enough waste each year to fill home and garage combined.

Newspapers, magazines, and throwaway advertisements …

Even earlier, during the fight against Germany and Japan, Los Angeles mandated limited recycling to help the war effort. Citizens separated metals for curbside pickup. Bound paper was returned to pulp mills; even cooking grease was saved for munitions. Those few who weren’t glad to help still complied, to avoid stiff fines.

Milk cartons and paper towels … and never-used, slightly dented goods, discarded at the factory …

After the war, people found themselves released from decades of privation into a sudden age of plenty. With the crisis over, recycling seemed irksome. A mayoral candidate ran on a one-issue promise, to revoke the inconvenient law. He won by a landslide.

Peanut hulls, fast-food bags, and takeaway pizza boxes …

The hills dividing L.A. had been formed as the Earth’s Pacific Plate ground alongside the North American Plate. As the two huge, rocky masses pressed and scraped, a coastal range squeezed out at the interface, like toothpaste from a tube. The Santa Monica Mountains and Hollywood Hills were mere offshoots from that steady accumulation, but they helped shape the great city that eventually surrounded them.

Boxes from frozen dinners, boxes from new stereos and computers, boxes from supermarket produce sections, boxes, boxes, boxes …

Between the hills once lay little valleys of oak and meadow, where mule deer grazed and condors soared—ideal out-of-view spots for landfills. The regiments of trucks came and went, day in and day out. Hardly anyone noticed until quite late that all suitable and legal crevices would be topped off within a single generation. By century’s end flat plains stretched between onetime peaks, eerily lit at night by tiki torches burning methane gas—generated underground by the decaying garbage.

Beer and soft-drink cans, ketchup bottles and disposable diapers … engine oil, transmission fluid, and electroplating residue … chipped ceramic knickknacks and worn-out furniture …

Harder times came. New generations arrived with new sensibilities and less carefree attitudes. Pickup fees were enacted and expensive processes found to stanch the flow … to cut the flood of trash in half, then to a tenth, then still more.

And yet that left the question of what was to be done with the plateaus between the hills. Plateaus of waste?

Plastic bottles and plastic bags, plastic spoons and plastic forks …

Some suggested building there to help relieve the stifling overcrowding—though of course there would be the occasional explosion, and a house or two could be expected to disappear into a sudden mire from time to time.

The family pet, sealed in a bag … hospital waste … construction debris …

Some suggested leaving the sites exactly as they were, so future archaeologists could find a wealth of detail from the prodigal middens of TwenCen California. With an even longer view, paleontologists speculated what the deposits might look like in a few million years, after grinding plates compressed them into layers of sedimentary stone.

Tires and cars, broken stereos and obsolete computers, missing rent money and misplaced diamond rings …

It might have been predictable, and yet few saw the answer coming. In a later day of harder times, of short resources and mandatory recycling, it was inevitable that those landfills should draw the eyes of innovators, looking for ways to get rich.

Iron, aluminum, silica … nickel, copper, zinc … methane, ammonia, phosphates … silver, gold, platinum …

Claims were filed, mining plans presented and analyzed. Refining methods were perfected and approved. Excavation began between the ancient hills.

Into a past generation’s waste, their desperate grandchildren dug for treasure.

The garbage rush was on.