The first electronic computer, known as the Electronic Numerical Integrator and Computer (ENIAC), began operation in 1945. Developed in the United States by John W. Mauchly and J. Presper Eckert, ENIAC was designed to perform complex calculations for the military during World War II. It was a groundbreaking advancement, utilizing vacuum tubes to process data at unprecedented speeds for that time, marking the transition from mechanical to electronic computing. ENIAC's development laid the groundwork for future computers, influencing design principles and operational concepts that are still in use in the technology of today.