The first general-purpose electronic computer is widely credited to the ENIAC (Electronic Numerical Integrator and Computer), which became operational in 1946 at the University of Pennsylvania. However, the history of computing machines stretches back much further. Early mechanical calculators and adding machines date to the 1600s, with Blaise Pascal's Pascaline (1642) and Gottfried Leibniz's Stepped Reckoner (1673) among the earliest. In the 1800s, Charles Babbage designed the Analytical Engine (though never fully built), which contained concepts foundational to modern programming. Electromechanical computers emerged in the early 1900s. The 1930s saw the development of early electronic computers like the German Z3 (completed in 1941), which some consider the first working programmable computer. The distinction between "first computer" depends on how you define the term—whether counting mechanical calculators, electromechanical machines, or fully electronic programmable systems. ENIAC is typically cited as the landmark because it was the first large-scale, general-purpose electronic digital computer, weighing 30 tons and occupying 1,800 square feet. Personal computers emerged in the 1970s with systems like the Apple II and Commodore, bringing computing into homes and offices.