At a gate topped by barbed wire just north of White Sands Missile Range, a miles-long line of vehicles formed before dawn on Saturday. Once or twice a year, the U.S. Army rolls this gate open so that ordinary citizens can set foot upon the precise patch of New Mexico desert where the first atomic bomb exploded. Civilian access to the site was first insisted upon in 1952 by members of a local church. They wanted to pray for peace in the place where humanity first tested the ultimate weapon of war. This year’s visitors did not come to pray, at least not outwardly. They were mostly tourists, many of them inspired by last year’s Oscar-winning biopic of J. Robert Oppenheimer, the director of the Manhattan Project. Thousands of them had massed at the base for an unholy pilgrimage.

They’d started lining up before 6 a.m., in lifted Ford F-150s and Cybertrucks, but also forest-green Subaru Outbacks and Hyundai EVs. When the line came to a standstill, people stepped out to stretch their legs. Between sips of coffee, they made small talk with one another. A few ventured off-road into the sage and creosote scrub. They photographed the sun as it rose over the mountains, casting a golden light upon America’s largest missile range.

Men in fatigues waved the first cars through a little after 8 a.m., sending a wave of excitement from the front of the line to the back. We were not allowed to go joyriding through all 3,200 square miles of White Sands. We had to follow a prescribed route past concrete structures that explosives had reduced to rubble and tangled rebar. We saw a progression of signs that formed a dark poem when read in sequence: Warning: Entering active missile range / Beware of eagles eating on the road. / Caution: Radioactive materials. The lettering on one had faded entirely, leaving only a crisply drawn rattlesnake. A few valleys over, local Paleo-Indians had once etched similar figures into brown basalt rock. After half an hour we crested a small hill, and in the distance I saw a pair of watchtowers with tinted windows standing guard over the Trinity Site, where the atomic age had dawned. It is still in full swing nearly 80 years later. Nuclear-armed nations are engaged in two major wars overseas, and a new three-way arms race has begun. I wanted to know what had become of the site and what it had to say to the world of today.

I parked in a makeshift dirt lot and made my way to the entrance, where two men stood next to a smoking barbecue selling breakfast burritos and danishes. At a concession stand nearby, cheaply made beanies and shot glasses were also for sale. Rain had fallen overnight, just as it had right before the Trinity test. The storm broke in the early hours, but a low bank of clouds had remained and settled directly over the site. Along the northern horizon, the Oscura mountain range reclined like a brown walrus in the sunlight. Similar ranges could be seen in almost every direction. In 1945, the Army hoped that these would serve as barriers, to hide the bomb’s enormous flash and keep its radiation in one place.

As the locals will tell you, that plan was not entirely successful. The National Cancer Institute estimates that some people downwind absorbed more than half a lifetime’s worth of natural radiation in the days after the test. Outside the base, about 15 members of the Tularosa Downwinders Consortium held signs reminding passersby of the cancers that have afflicted generations of their families. I’d stopped to hear their stories, and asked them if they’d ever been inside the site. One of the protesters, Doris Walters, told me that she’d come in once, but her visit lasted only five minutes before she was overcome by horror and had to leave. Tina Cordova, who co-founded the consortium, said that she had no interest. She said it was a shame the way the site had been turned into a carnival.

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The fenced path into the Trinity Site led directly to its centerpiece: a dark lava-rock obelisk, a kind of sinister twin to the Washington Monument. It was placed exactly where the hundred-foot steel tower that held the bomb once stood. All that’s left of the tower are a few wrist-thick bits of steel that once made up part of its lower legs. The rest was vaporized or otherwise destroyed by the blast. Families posed in front of the obelisk, smiling, as though it were a pair of wings on a brick wall in Nashville, or some other mural backdrop for selfies. At one point, a content creator began recording himself while his friend held up a script on a clipboard. He needed six takes to nail the opening sentence. (“On July 16 … the world changed forever.”) Later, two men positioned themselves on either side of the obelisk and unfurled a Buffalo Bills banner.

People had come to the site for different reasons. In the line to approach the obelisk, I spoke with a Texan named Gary Neighbors. He sported blue jeans, work boots, and a snow-white handlebar mustache, and by his side, he had a gentle Australian shepherd mix named Festus. Neighbors told me that during the final months of World War II, his father had been stationed at the Army Air Corps base in Carlsbad, California, and that he’d later claimed to have seen a flash in the sky on the morning of the Trinity test. Whether light from the explosion had been visible that far away or not, Neighbors couldn’t say for sure, but either way, he wanted to come and honor his dad’s memory.

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The Trinity Site seemed to excite lots of feelings between fathers and sons. A man named Andy told me that he’d left Mississippi in his car two days before, then stopped in Missouri to pick up his dad on the way. They shared a long-standing interest in the nuclear sublime. Andy said that he’d come “this close” to joining the Nuclear Navy. He and his dad shared an appreciation for the engineering details of the Manhattan Project. They liked that it harnessed the whole range of human ingenuity, from the rarefied, cerebral realm of theoretical physics to the taped-together nature of the bomb itself. It had been assembled by hand, after all, not in a white-walled lab in Los Alamos, but in a small, vacant ranch house just a few miles away.

I spent the rest of my visit roaming the eerie, fenced-in area around the obelisk. It is still haunted by a ghostlike radioactivity. While I was there, three millirems of it likely passed through my skin into my blood vessels, my muscle tissue, and even my brain. That’s about a mammogram’s worth of radiation, not enough to endanger a visitor, but enough to contribute to the general aura. As a historical site, Trinity has no obvious analogues, but being there did remind me of a disquieting hike that I took earlier this year, amid the black trunks of a redwood forest that had burned in a fire a few years ago.

I wondered what it was like to be there on that early morning in July 1945. Oppenheimer’s director, Christopher Nolan, told me that when he went to depict the Trinity test on film, he wanted it to be massively threatening and hypnotically beautiful. The second part is important for historical accuracy. Those who saw the blast firsthand, still weeks before the horrors of Hiroshima and Nagasaki, were awestruck by the pure spectacle. Joan Hinton, one of the only women who worked as a nuclear scientist on the Manhattan Project, wasn’t on the official list that morning, but she snuck in to see the test anyway. She said that she felt like she was standing on the seafloor, looking up into an ocean of white light that then turned purple and blue.

Sand from the desert below was swept up into the mushroom cloud. In midair, the grains melted and fused together with plutonium and metals from the bomb. Pebbles of a glassy, jade-colored material—later named Trinitite—formed, and then poured back down, like hail, into the fresh crater below. Most was removed back in 1953, when the Army leveled the site with bulldozers, but tunnel-digging ants occasionally push pieces of it up to the surface. Trinitite’s rarity has made it a collector’s item: It may not exist anywhere else in this galaxy. Removing it from the site is illegal, but lots of people were looking for it anyway. I saw a man showing a chunk from his private collection to an assembled crowd. When he held a Geiger counter to it, the machine’s steady clicks blurred into a thrum.

Perhaps the Army should have left the crater intact, so that more explicit evidence of the Trinity test, and its terrible power, would linger in the ground, just in case. The success of the Manhattan Project made a truly hellish set of futures possible for our species, up to and including our extinction. A crater full of Trinitite could have been left to live out its half-life as a reminder of what happened here, and of what could still happen if we ever have a major nuclear exchange. If our civilization suffers some kind of severe discontinuity, future archaeologists may need to dig this place up to get a hint as to how things went so wrong.