ENIAC Day, also known as the World’s First Computer Day, is observed worldwide every February 15 to celebrate the Electronic Numerical Integrator and Computer (ENIAC), one of the earliest electronic general-purpose computers. The day marks the formal dedication of ENIAC at the University of Pennsylvania on February 15, 1946, following its development by J. Presper Eckert and John Mauchly, which began in 1943 as a secret U.S. Army project. Initially designed to calculate artillery firing tables, ENIAC later contributed to research on thermonuclear weapons. The day also highlights the contributions of ENIAC's first six programmers, all women, whose work remained largely unrecognized for decades. ENIAC Day was officially inaugurated by the City of Philadelphia in 2011 to commemorate the 65th anniversary of ENIAC's unveiling. Celebrations typically involve educational events and recognition of the historical significance of computing technology.