Trinity Site

At 5:29 on the morning of July 16, 1945, scientists from Los Alamos exploded the first atomic bomb on a steel tower in the Jornada del Muerto, on ground that is now the Army's White Sands Missile Range. Ground zero is marked by a dark obelisk of lava rock inside a fenced circle. A short drive away stands the McDonald ranch house, where the bomb's plutonium core was assembled in the days before the test.

The site opens to the public once a year, on the third Saturday in October, through the Stallion Gate on NM-525, reached from US-380 east of San Antonio. The visit is self-guided and free; photographs are allowed at ground zero and the ranch house, there is no fuel anywhere on the range, and the Army's own figure is that an hour at ground zero adds about half a millirem of radiation.

The people who lived downwind were told nothing. Ranching and farming families across the Tularosa Basin and beyond went on living with the fallout, and many of their children and grandchildren count generations of cancers since. When Congress passed the Radiation Exposure Compensation Act in 1990, it paid downwinders of the Nevada test site and left New Mexico's out. The Tularosa Basin Downwinders Consortium, founded in 2005 by Tina Cordova and others, pressed for two decades to change that, and in July 2025 an expansion of the law finally covered them and their families.

A state sign honoring the downwinders went up outside the missile range on the test's eightieth anniversary, and Congress has since ordered the Defense Department to raise monuments to them at White Sands and at Holloman Air Force Base.