Ice House

A shingle roof sits atop stone corner posts, surrounded by a grassy lawn
This memorial commemorates the building where the world's first atomic device was assembled.


Quick Facts
Los Alamos, NM

Historical/Interpretive Information/Exhibits

In this building, originally designed to store ice, scientists assembled the world’s first nuclear device.  

When the Manhattan Project acquired the Los Alamos Ranch School, engineers took advantage of the existing buildings, including a small icehouse on the bank of Ashley Pond. Project Y’s laboratories and support buildings soon surrounded the icehouse.  

As plans for an implosion-type weapon neared completion, scientists still had their doubts about their design. They needed to conduct a full-scale test to demonstrate whether the weapon actually worked. A test device, known as the Gadget, became the world’s first atomic device; its nuclear components assembled at the icehouse-turned-laboratory. The Gadget was detonated on July 16, 1945, at the Trinity test site on the Alamogordo Bombing Range.

Continue Your Journey

As you walk around downtown Los Alamos, you can explore the Los Alamos Historical Society campus, which includes the Los Alamos History MuseumHans Bethe House, Fuller Lodge, Romero Cabin, and Ancestral Pueblo Site. 

Just across Central Ave from Fuller Lodge you'll find Ashley Pond, another centerpiece of the Los Alamos community. The Bradbury Science Museum has interactive exhibits that share stories from the Manhattan Project and provide a glimpse of historic sites “behind the fence.” 

Manhattan Project National Historical Park

Last updated: April 12, 2022