ssor 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."

JUMBO

Lying next to the entrance of the chain link fence that still surrounds
Trinity Site are the rusty remains of Jumbo. Jumbo was the code name for
the 214-ton Thermos shaped steel and concrete container designed to hold
the precious plutonium core of the Trinity device in case of a nuclear
mis-fire. Built by the Babcock and Wilcox Company of Barberton, Ohio,
Jumbo was 28 feet long, 12 feet, 8 inches in diameter, and with steel
walls up to 16 inches thick.

The idea of using some kind of container for the Trinity device was
based on the fact that plutonium was extremely expensive and very
difficult to produce. So, much thought went into a way of containing
the 15 lb. plutonium core of the bomb, in case the 5,300 lbs. of
conventional high explosives surrounding the core exploded without
setting off a nuclear blast, and in the process scattering the costly
pl