Behind the Fence at Los Alamos | Inside the Manhattan Project’s Hidden Sites

What lies “behind the fence” at Los Alamos? Twice each year, visitors get a rare opportunity to enter one of the most historic and restricted areas of Los Alamos National Laboratory. Now, you can experience that journey from anywhere. In this virtual tour of Manhattan Project National Historical Park, you'll step inside places where scientists raced to unlock the secrets of plutonium, tested the explosive design that would change the world and grappled with the dangers of a brand-new atomic age. Along the way, park rangers, historians, and Laboratory experts reveal the stories behind these remarkable sites—and the people who worked there. This is Manhattan Project history like few ever get to see. Featured locations: • Pond Cabin • Battleship Bunker • Slotin Building • Historic Pajarito Site (TA-18) • Hillside Vaults • Ancestral Pueblo cavates LA-UR-26-23857