Los Alamos has haunted me since the first time I went there, nearly three years ago. It has a fascinating history, tempered with secrecy and drive, fear and heartache–in short, all the things that make us human. So of course I had to go back this time around, when I could take my time exploring, not worried about keeping twenty teenagers out of trouble in the “Atomic City.”

Before it was the home of the Manhattan Project, it was home to a boys’ ranch school, modeled after the Boy Scouts and started in 1917 by Ashley Pond. The Army seized the ranch property in 1942, transforming it into Site Y, and built housing for the scientists who would follow. The “town that didn’t exist” built itself around the project, using the school’s existing buildings as housing for the scientists, offices, and a dining hall.

The museum, itself one of the buildings used by the scientists, has a moving collection of letters from engineers who were called to work on “the gadget.” In letters that were returned because they revealed too much information, the writers explain how they were all given the same address–a P.O. box in Santa Fe, which was also put on driver’s licenses and birth certificates. They sometimes refer to their work, in no detail, saying they weren’t sure exactly what their work had to do with the war effort.

In later letters, they sometimes mention the moment when they learned how their engineering was used. The accounts range from curious to heartbreaking, and I have to wonder what it was like to be driven over thirty miles into the desert, to work on a tiny part of something, its purpose unknown, and then to see the headline in 1945 that revealed the result of their secret collaboration.

One room in the museum is devoted to the aftermath of Fat Man and Little Boy, a series of unearthly panoramic photographs that are difficult to look at. An adjoining room displays an array of atomic kitsch–from board games and candy (this is after all, the birthplace of the Atomic Fireball) to ladies’ hats and a celebratory cake that feature the iconic mushroom cloud. Down the street, the Bradbury Science Museum offers more views on the history and technology behind the Manhattan Project, but its most intriguing room is one that is a gallery of photographs. The walls are filled with rows of 8 x 10 black and white photos of people who worked at the lab in

the 1940s. They are scientists, housekeepers, cooks, engineers, pilots and colonels, all with gray hair and weathered faces. Each one is paired with a statement, in their own words, that describes what they felt while working for the project, and how they felt after they learned of its purpose. It’s deeply moving, reading these accounts, and surprising to see what was salvaged and what was destroyed–beyond letters, uniforms, and board games.

The Atomic City still seems shrouded in mystery. When I ask if the national lab is open to the public for tours (it seems reasonable, after all everyone else is offering tours), the docent looks shocked and says, “Oh, no.” And there is no further explanation. A friend in Albuquerque tells me, “Nobody really knows what goes on there, or who does what. But you can still tell who’s who, mainly by their shoes.”

Many of the buildings used by the scientists are now being transformed yet again. The Fuller Lodge, formerly the dining hall, is now a community arts center, hosting classes and a gallery space for local artists. Another building is now the town playhouse, and many of the historic homes on Bathtub Row are private residences. If you know where to look, you can find Oppenheimer’s former house.

Leaving town, I have more questions than answers: what is being preserved, and what is being transformed? What has been salvaged, and what has been lost in the memory of time?