Trinity Site

Black and white photo of an atomic explosion in a flat desert.
The Trinity Test, July 16, 1945.


At 5:30 am mountain war time on July 16, 1945, an accumulation of scientific research culminated in the detonation of the world’s first atomic test device, codenamed the “Gadget” at the Alamogordo Gun Range. The explosion was more massive than scientists predicted. In a flash of blinding light and thunderous sound, a mushroom cloud  38,000 feet (11,582 m) tall consumed the sky. This nuclear explosion was visible over 280 miles (450 km) away. While this detonation ushered in the nuclear age, the Trinity Test exposed local people who lived near or downwind from the blast to dangerous levels of radiation, leading to long lasting impacts on residents’ health. Those who lived near the blast site, or downwinders, continued to feel the effects of this radiation for decades to come. Learn more about the Trinity Test through the articles below.
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    Last updated: April 10, 2023

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