On July 16, 1945, deep in the deserts of New Mexico, Pandora's Box was opened, and the Atomic Age was born.
Trinity was code for the first detonation of "The Gadget", a nuclear device, conceptually similar to its devastating cousin, "Fat Man". Fat Man was infamously detonated over Nagasaki three weeks later, killing between 40,000 to 75,000 people in the immediate blast. Coupled with the earlier bombing of the city of Hiroshima, the world watched in unfolding horror as the fallout continued to take lives by way of radiation poisoning and cancer for decades. The attacks by the U.S on Japan during WWII were the first and last time that the catastrophic weapons were employed during a war.
While the U.S. military may not have had to foresight to grasp the awesome destruction that a 13-pound plutonium device could have on a population long term, they knew what it could do on initial contact, because Trinity gave them a good show. The 600 ft. wide fireball turned obliterated trees, turned sand into glass, and blew out windows 120 miles away.
Normally off limits to civilians, the desolate scene of Trinity's detonation is open to the public on the first Saturday of April and October every year. The military opens up the fences surrounding ground zero and you can peruse the gift shop for bomb-related knick knacks, peek into a bunker, search for remnants of "Trinitite", the scattered glass crerated by the blast, or check out a sobering piece of military history, Fat Man's bomb casing.
While there are quite a few things to see around the perimeter of the the blast site, ground zero is sober and sparse. At the exact center of the blast, a black lave rock obelisk was erected, and you can see what remains of the obliterated tower that The Gadget was detonated on. A plaque on the obelisk reads simply:
"Trinity Site Where The World's First Nuclear Device Was Exploded On July 16, 1945
Erected 1965 White Sands Missile Range J Frederick Thorlin Major General U.S. Army Commanding"
White Sands Missle Range is a military base, so be prepared to show proper I.D. and follow instructions referring to authorized and unauthorized areas of the site.
While only open to "atomic tourists" two days out of the year, there is a historic marker on US 380, located near the Stallion Gate turnoff.