Detail of the back of a section of ENIAC, showing vacuum tubes

ENIAC (which meant "Electronic Numerical Integrator And Computer") was a computer built between 1943 and 1946. It was designed by two people called John Mauchly and J. Presper Eckert. The machine was built out of nearly 17,500 vacuum tubes, 7,200 diodes and many miles of wire. It took up 1,800 square feet (170 m²) of space, which is the size of a large room.