ENIAC, or Electronic Numerical Integrator and Computer, was one of the first general-purpose electronic digital computers. Completed in 1945, it was designed to perform complex calculations for the U.S. Army during World War II. ENIAC used vacuum tubes for processing and could execute thousands of operations per second, making it a groundbreaking advancement in computing technology. The machine was massive, occupying about 1,800 square feet and weighing nearly 30 tons. It consisted of 40 panels and required a significant amount of electricity to operate. John W. Mauchly and J. Presper Eckert were the primary engineers behind ENIAC, paving the way for future developments in computer science.