Scattered across a neighborhood in central Kabul are the ruins of another empire come and gone from Afghanistan.

Tattered sandbags and piles of discarded barbed wire. Metal hulls of tank traps sitting unused on the side of the road. Red-and-white metal barriers, once lowered to stop vehicles at checkpoints manned 24/7, permanently pointing toward the sky.

Not that long ago, this neighborhood — known as the Green Zone — was a diplomatic enclave, buzzing with the soundtrack of a multibillion-dollar war effort in Afghanistan. Armored vehicles rumbled down the streets, shuttling Western diplomats and high-ranking Afghan officials, while the thud-thud-thud of American helicopters echoed across the sky above.

But these days, there’s another kind of buzzing in the neighborhood: the Taliban moving in and making it their own. Like their American-supplied rifles and Humvees and military fatigues, the Green Zone is becoming the latest vestige of the Western war effort that the Taliban have repurposed as they build up their own military and government.

Well-to-do officials with the Taliban administration and their families have settled into the dwellings abandoned by Western officials since the collapse of the former government in August of 2021 and the flight of most of the Green Zone’s residents. Inside what was a compound of the British embassy, young men dressed in gray-and-black turbans and traditional brown shawls gather each afternoon for classes in a new madrasa, a school for Islamic instruction. Security forces with the new government zip in and out of NATO’s former headquarters.

The neighborhood, and its nearly indestructible blast walls, have become a testament to the enduring legacy of occupation, a reminder that even when foreign forces depart, the physical imprint they leave on a country’s landscape — and national psyche — often lives on, indefinitely.

“These walls will never be torn down,” said Akbar Rahimi, a shopkeeper inside the Green Zone, summing up the seeming permanence of the infrastructure around him.

One recent afternoon, Mr. Rahimi, 45, sat behind the wooden counter of his corner store, absent-mindedly watching a Bollywood movie on the TV mounted to the wall. On the street outside, a forest green maintenance vehicle with a poster of a young Mullah Omar — the founder of the Taliban movement — plastered on the windshield raced past.

Mr. Rahimi perked up as three young men, former Taliban fighters turned security guards, entered the shop and rummaged through a pile of small, dirt-encrusted lemons by the front door. They handed the lemons to Mr. Rahimi, who weighed them on a rusty scale and tied them into a plastic bag in a single, masterful flip of the wrist.

“We’re buying lemons because some of our friends are fat — they need lemons to get thin and be better prepared for security,” one of the men joked. His friends burst out laughing. Mr. Rahimi, unamused, handed them the lemons and took a tattered bank note in return.

Mr. Rahimi remembers the old Green Zone and its former residents with a sense of nostalgia. Outside the neighborhood, the city was regularly torn apart by suicide blasts and targeted assassinations during the American-led war. But within its roughly one-square-mile radius, there was an intoxicating sense of lawfulness.

White-collar Afghan employees in government offices and foreign embassies used to pour down the street outside his shop at 8 a.m. each morning as they arrived for work and again at 4 p.m. when they headed home. For him, that reliable daily rhythm seemed to offer a sense of control, a predictability that had eluded Afghanistan for decades.

There was “order and discipline,” he said, wistfully.

For most of the two-decade war, the Green Zone occupied a unique place in Kabul’s collective consciousness. Once a leafy green upper-middle class neighborhood with tree-lined streets, elegant villas and a grand boulevard, the area transformed into a dull gray fortress of 16-foot-tall concrete barriers.

To some Afghans who could not enter it, the impenetrable void that sprawled across central Kabul was a source of deep resentment — an alien presence disrupting daily life.

To others, it was a harbinger of the eventual loss of the war, a place where despite Western generals’ assurances about battlefield victories and milestones reached, the steady build up of blast walls and barricades offered a more honest assessment of the West’s failures to curb the Taliban’s reach.

When the Taliban took over Kabul, they initially eyed this concrete slab of the city with suspicion. For months, agents with the intelligence wing of the nascent Taliban administration went building to building, digging through the remains of an enemy whose inner workings had been shrouded in mystery for 20 years. Every home was presumed to have hidden weapons or trip wires. Every surveillance camera was a sign of espionage.

Faizullah Masoom, a 26-year-old former Taliban fighter from Ghazni Province, felt awe-struck when he first saw the Green Zone. Then, a feeling of pride washed over him.

“I said to myself that our enemy with such defenses — blast walls and security cameras, barricaded areas and fortified buildings — were finally defeated by us,” he said. “We were always in the mountains, forests and fields. We only had one gun and a motorcycle.”

Now, Mr. Masoom rarely leaves the Green Zone.

Soon after the Taliban seized power, he assumed a new post as a security guard at a checkpoint outside an office building. One recent afternoon, he sat on a concrete barrier with three other guards at their post near the former Italian embassy.

The men passed around a bag of chewing tobacco as pickup trucks and armored cars carrying officials with the Taliban administration pulled up to the metal barrier. They beckoned for the drivers to lower their blackened windows, looked around the inside of the vehicles and ushered them through the gate.

As I turned to leave, Faizullah asked where I was from. When he heard “America,” his eyes grew wide and mouth dropped.

“She’s from America?” he asked a New York Times colleague who was with me, almost in disbelief. For 20 years, Americans were a faceless enemy. Now one was standing two feet in front of him.

He and his friends looked at each other bewildered for a few seconds — a sense of uncertainty hanging in the air. Then they burst out laughing.

“We have no conflict, war or enmity with anyone anymore,” he said smiling, as if to reassure me.

But the significant presence of security guards here — much like the blast walls that remain in place — reflects the insecurity that threatens the country’s fragile peace since the American-led war ended. While the days of constant airstrikes and night raids are over, suicide attacks from terrorist groups continue to plague the city — even as the guardians charged with keeping them at bay have changed.

Down the road from their post, the words “Long Live the Islamic Emirate of Afghanistan” — the official name the Taliban have given their government — are inscribed on a blast wall in white paint, one of a number of cosmetic changes the new government has instituted as it remakes the area in its own image.

The most striking example is painted on a wall that buttresses the former U.S. Embassy. The wall bears a mural depicting a vertical American flag, with columns of red stripes holding up white-on-blue stars. Beside the flag, a dozen hands are pushing down the red columns as if toppling a series of dominoes. “Our nation defeated America with the help of God” is scrawled next to it in blue paint.

The embassy itself remains empty and untouched — or mostly untouched.

Affixed to the towering metal and barbed wire gates is a metal plaque painted with the emblem of the United States: a bald eagle, wings outstretched, an olive branch in one talon and 13 arrows in the other. Over two dozen bullet holes have chipped the paint.

Safiullah Padshah contributed translation from Kabul.