“Now I am become death, the destroyer of worlds.”

That line, paraphrased from the Hindu Bhagavad Gita, crossed Robert Oppenheimer’s mind as he became a witness to history. On July 16, 1945, at 5:29:45 AM (MT), the first atomic bomb ever detonated went off near Socorro, New Mexico. Seventy years later, we’re still feeling the political and scientific shockwaves of this high-stakes experiment.   

1. Eight Different Sites Were Considered.

U.S. military officials started looking for a suitable location in May 1944. The barrier sand reefs over by south Texas were assessed, as was an island off California’s southern coast and Rice, California (now a ghost town). Colorado's San Luis Valley region was also under consideration. 

New Mexico alone presented four separate options: the Tularosa basin, an expanse near Cuba, the deserts south of Grants, and—finally— a parched, 90-mile stretch called “Jornada del Muerto,” or “route of the dead men.” After much discussion, the latter spot was chosen. As a remote locale with an abundance of wide open space, it offered many pluses. What's more, it wasn’t far from Los Alamos, where the Manhattan Project’s bombs were under development. Base camp construction started that fall.

2. Nobody Knows Where the Code Name “Trinity” Came From.

Oppenheimer took the credit, but forgot all about his own source of inspiration. “Why I chose this name is not clear,” he admitted in a 1962 conversation with General Leslie Groves. Still, the well-read physicist did hazard some guesses. As the fateful day approached, Oppenheimer often thought of John Donne, a 17th-century poet whom he greatly admired. Invoking Christianity’s Holy Trinity, Donne began one famous sonnet with “Batter my heart, three person’d God.” But, confessed Oppenheimer, “Beyond this, I have no clues whatsoever.”

3. There Was a Rehearsal.

108 tons of TNT were placed atop a twenty-foot wooden platform and blown up on May 7, 1945. Among other things, the helpful run-through allowed everyone to calibrate their data collection equipment.     

4. Edward Teller Feared That the Test Might Ignite Earth’s Atmosphere.

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Work came to a grinding halt (at least by some accounts) when this “father of the hydrogen bomb” presented his doomsday scenario. Fission explosions, like the one America’s first nuke would create, produce unbelievable heat—think tens of millions of degrees Fahrenheit. Teller feared that this’d be hot enough to fuse nitrogen atoms throughout our planet’s atmosphere, kicking off a catastrophic release of energy. Without warning, the whole human race might be incinerated. Obviously, this was no minor concern. 

Common sense demanded an investigation. “Better to accept the slavery of the Nazis than to run a chance of drawing a final curtain on mankind,” Nobel laureate Arthur Compton would later say. Luckily, further analysis disproved Teller’s nightmarish theory. 

5. The Team Ran a Betting Pool on How Big Their Explosion Would Be.

Teller wagered that it would equal 45,000 tons’ worth of TNT.  Hans Bethe went with 8,000 tons. For his part, Oppenheimer not only chose a meager 300 tons but privately bet another associate $10 that the whole test would be an abject failure. In contrast, General Groves started getting annoyed when Enrico Fermi “offered to take wagers from his fellow scientists on whether or not the bomb would … merely destroy New Mexico or the entire world.”   

6. The Fireball Was Seen as Far as 180 Miles Away.     

Upon going off, the finished product wielded enough force to match around 20,000 tons of TNT. It also let loose a radiant burst of light which startled witnesses in Albuquerque, Santa Fe, Silver City, and El Paso. 

One Rowena Baca of San Antonio, NM, only 35 miles away, suddenly found herself being shoved under a bed by her grandmother, who mistook Trinity’s handiwork for “the end of the world.” And while flying out near Albuquerque that morning, Navy pilot John R. Lugo initially thought he was watching the sun rise—from the south.

7. At First, Civilians Were Told that It Was a Simple Military Blunder.

The armed forces appeared to clear things up by releasing this statement (a carefully-written cover story), which ran in New Mexican papers hours after the fact:     

Several inquiries have been received concerning a heavy explosion which occurred on the Alamogordo Army Air Base reservation this morning. A remotely located ammunition magazine containing a considerable amount of high explosive and pyrotechnics exploded. There was no loss of life or injury to anyone, and the property damage outside of the explosives magazine itself was negligible. Weather conditions affecting the content of gas shells exploded by the blast may make it desirable for the Army to evacuate temporarily a few civilians from their homes. 

Ordinary Americans would be kept in the dark about what had really happened until after the Japanese bombings.  

8. The Trinity Bomb Used the Same Design as the One That Was Dropped on Nagasaki 24 Days Later.

Whereas a uranium-based weapon (nicknamed “Little Boy”) laid Hiroshima low, Nagasaki’s bomb (a.k.a.: “Fat Man”) relied on plutonium. The former was fairly simple and the scientists were confident it didn’t need testing, but the latter was more complicated, requiring that a core filled with this dangerous element implode before it could explode. 

9. “Trinitite” is a Glassy Substance Created in the Historic Blast.

Bits of southwestern sand were transformed by the unnatural heat, reborn as a peculiar glass-like material. Today, one can’t legally go out in the field and gather trinitite, which—by the way—is radioactive, though it becomes less so over time.  

10. You Can Visit a House that Survived the Whole Ordeal.  

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Most of the windows were shattered, some roofing flew off, and the roof itself bowed inward. But otherwise, the George McDonald ranch house remained more or less intact, despite standing only two miles away from Trinity’s ground zero. "Abandoned" by its original owners in 1942 (although they did stage a high profile armed occupation of the area in 1982), Manhattan Project personnel repurposed the building’s bedroom as a bomb assembly zone. Since then, it’s been renovated and nuclear tourists are allowed to drop by on select days.