Intense Secrecy

Due to the intense secrecy surrounding the test, no accurate information of what happened was released to the public until after the second atomic bomb had been dropped on Japan. However, many people in New Mexico were well aware that something extraordinary had happened the morning of July 16, 1945. The blinding flash of light, followed by the shock wave had made a vivid impression on people who lived within a radius of 160 miles of ground zero. Windows were shattered 120 miles away in Silver City, and residents of Albuquerque saw the bright light of the explosion on the southern horizon and felt the tremor of the shock waves moments later.

The true story of the Trinity test first became known to the public on August 6, 1945. This is when the world's second nuclear bomb, nicknamed Little Boy, exploded 1,850 feet over Hiroshima, Japan, destroying a large portion of the city and killing an estimated 70,000 to 130,000 of its inhabitants.Three days later on August 9, a third atomic bomb devastated the city of Nagasaki and killed approximately 45,000 more Japanese. The Nagasaki weapon was a plutonium bomb, similar to the Trinity device, and it was nicknamed Fat Man. On Tuesday August 14, at 7 p.m. Eastern War Time, President Truman made a brief formal announcement that Japan had finally surrendered and World War II was over after almost six years and 60 million deaths!

On Sunday, September 9, 1945, Trinity Site was opened to the press for the first time. This was mainly to dispel rumors of lingering high radiation levels there, as well as in Hiroshima and Nagasaki. Led by General Groves and Oppenheimer, this widely publicized visit made Trinity front page news all over the country.

Trinity Site was later encircled with more than a mile of chain link fencing and posted with signs warning of radioactivity. In the early 1950s most of the remaining Trinitite in the crater was bulldozed into a underground concrete bunker near Trinity.  Also at this time the crater was back filled with new soil. In 1963 the Trinitite was removed from the bunker, packed into 55-gallon drums, and loaded into trucks belonging to the Atomic Energy Commission (the successor of the Manhattan Project).  Trinity site remained off-limits to military and civilian personnel of the range and closed to the public for many years, despite attempts immediately after the war to turn Trinity into a national monument.

In 1953 about 700 people attended the first Trinity Site open house sponsored by the Alamogordo Chamber of Commerce and the Missile Range. Two years later, a small group from Tularosa, NM visited the site on the 10th anniversary of the explosion to conduct a religious service and pray for peace.

Regular visits have been made annually in recent years on the first Saturday in October instead of the anniversary date of July 16, to avoid the desert heat.  Later Trinity Site was opened one additional day on the first Saturday in April. The Site remains closed to the
public except for these two days, because it lies within the impact areas for missiles fired into the northern part of the Range.

In 1965, Range officials erected a modest monument at Ground Zero. Built of black lava rock, this monument serves as a permanent marker for the site and as a reminder of the momentous event that occurred there. On the monument is a plain metal plaque with this simple inscription: "Trinity Site Where the World's First Nuclear Device Was Exploded on July 16, 1945."

During the annual tour in 1975, a second plaque was added below the first by The National Park Service, designating Trinity Site a National Historic Landmark.  This plaque reads, "This site possesses national significance in commemorating the history of the U.S.A."