Short for Electronic Numerical Integrator And Calculator, the ENIAC was invented by J. Presper Eckert and John Mauchly at the University of Pennsylvania and began construction in 1943 and was not completed until 1946. It occupied about 1,800 square feet, used 17,468 vacuum tubes, 15,000 relays, weighing almost 50 tons, uses 200 Kilowatts of electricity, and cost $500,000. While not completed until the end of the World War II, the ENIAC was created to help with the war efforts against German forces. In the picture to the right, is a public-domain U.S. Army Photo of the ENIAC, from K. Kempf. and the History of Computing.