Our teenage son Will runs his hand across the 10-foot-long, canary yellow replica of an atomic bomb that weighed 10,800 pounds. The plump, round, plutonium-fueled device was given the code name “Fat Man,” for obvious reasons. The actual Fat Man destroyed Nagasaki, Japan, on Aug. 9, 1945. Little Boy, a slimmer bomb triggered by enriched uranium, had leveled Hiroshima a few days before that.

The models of the two bombs that launched us into the Nuclear Age can be seen — and unlike the real, radioactive items, touched — at the Bradbury Science Museum in Los Alamos, N.M., famously known as Atomic City.

During World War II, scientists at the isolated, clandestine laboratory complex atop the volcanic Pajarito Plateau in the Jemez Mountains designed and built the world’s first nuclear weapons as part of the historic Manhattan Project. (The city of Los Alamos itself was built after World War II, to support the people who worked at the lab.)

Because we were in Santa Fe on a family vacation, the Rio Grande separating that artsy town from science-oriented Los Alamos like the fissure between right and left brains, we drove my aspiring physicist 45 minutes northwest of Santa Fe to the “town that never was” so that he could explore the New Mexico segment of the Manhattan Project National Historical Park, added to the list of national parks in 2015. (The other two sections are in Oak Ridge, Tenn., and Richland, Wash.)

Visitors are greeted by sculptures of the Manhattan Project’s co-leaders, Brig. Gen. Leslie Groves Jr. of the U.S. Army Corps of Engineers and J. Robert Oppenheimer, a theoretical physicist from the University of California-Berkeley.  The complex today is now downtown Los Alamos, and encompasses…