Photo Essay: Trinity Site

I put together these historical “then and now” photos after visiting Trinity Site for the LANL magazine, National Security Science. Trinity Site, located in southern New Mexico, is where the first atomic bomb, Trinity, was detonated on July 16, 1945. Credit: Los Alamos National Laboratory. LA-UR 21 25571

Ground zero is viewed from the top of Compaña Hill (also called Compania Hill or Cerro de la Colorado) in 2021 and 1945.

Manufactured in Ohio by Babcock & Wilcox, Jumbo was originally 25 feet long, 10 feet in diameter, and weighed 214 tons. Scientists planned to use Jumbo to contain the Trinity test but then changed their minds.

The Trinity test was detonated atop a 100-foot tower, perhaps to help ensure clear photos of the expansion of the fireball. These photos were used to help determine the device’s yield and other blast effects.

Jennifer Talhelm, of the Lab’s Public Affairs group; Nicholas Lewis and Alan Carr, both of the National Security Research Center; and Mark Chadwick, of the Weapons Physics directorate, leave the McDonald Ranch House, where the Trinity device was assembled in 1945.

The Compaña summit (elevation 5,700 feet) provided a good spot for scientists to watch the Trinity test in 1945.