Los Alamos: Behind the Fence

Three men surround a large metal orb inside a white tent.
Louis Slotin (in sunglasses) pictured with the Gadget in 1945.



Even today, many places associated with the Manhattan Project in Los Alamos are located on secure federal Department of Energy reservations and cannot be easily accessed by members of the public. Read the articles below for a glimpse behind the Manhattan Project fences and learn about the places with no or limited public access.  

Manhattan Project NHP tour offered by Los Alamos National Lab to take visitors to three historic buildings including Pond Cabin, a building that Nobel Laureate Emilio Segrè and his team used. Visitors will also see Battleship Bunker, a building used for implosion diagnostic testing, and the Slotin Building where physicist Louis Slotin succumbed to a deadly criticality accident. These tours are only offered three times a year. Reservations are required. 

On July 16, 1945, at 5:29 am Mountain War Time, scientists and military officials detonated the world’s first atomic device, known as the “Gadget.” The location of this test, known as the Trinity Site, is located on White Sands Missile Range and is closed to the public. Twice a year, the US Army hosts a Trinity Site Open House when the public may visit Trinity Site. 

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    Last updated: May 4, 2023

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    Manhattan Project National Historical Park
    c/o NPS Intermountain Regional Office
    P.O. Box 25287

    Denver, CO 80225-0287


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