First pile scientists at the University of Chicago on December 2, 1946, the fourth anniversary of their success.

Back row, left to right, Norman Hilberry, Samuel Allison, Thomas Brill, Robert G. Nobles, Warren Nyer, and Marvin Wilkening. Middle row, Harold Agnew, William Sturm, Harold Lichtenberger, Leona W. Marshall, and Leo Szilard. Front row, Anderson. Enrico Fermi, Walter H. Zinn, Albert Wattenberg, and Herbert L. Anderson.