Until recently most Europeans interested in computing would have claimed that the first electronic computer was the Colossus, designed and constructed in Bletchley, England, by the mathematician Alan Turing and his colleagues, operational in December 1943 and used to decipher the German Enigma code, with a decisive effect on the course of World War II. Most Americans, on the ther hand, would have given the honor to the Electronic Numerical Integrator and Calculator, built by John W. Mauchly and J. Presper Eckert at the Moore School of Electrical Engineering, University of Pennsylvania, and operational in late 1945.