The Analytical Engine was a proposed mechanical general-purpose computer designed by English mathematician Charles Babbage.
It was first described in 1837 as the successor to Babbage's Difference Engine, a design for a mechanical computer. The Analytical Engine incorporated an arithmetic logic unit, control flow in the form of conditional branching and loops, and integrated memory, making it the first design for a general-purpose computer that could be described in modern terms as Turing-complete.
Babbage was never able to complete construction of any of his machines due to conflicts with his chief engineer and inadequate funding.
The first complete Babbage Engine was completed in London in 2002, 153 years after it was designed. Difference Engine No. 2, built faithfully to the original drawings, consists of 8,000 parts, weighs five tons, and measures 11 feet long.