Z3Konrad Zuse's computer Z3 was the first working freely programmable, fully automatic machine, which are often used as criteria in defining a computer. It was built with relays, had a clock frequency of 5.33 Hz and was completed in 1941.
The original Z3 was destroyed in 1944 during a bombardment. A fully functioning replica was built in the 1960s by the Zuse KG and is on permanent display in the Deutsches Museum. In 1998 it was proved to be Turing-complete.