An electromechanical programmed calculator built in Berlin by Konrad Zuse and fully operational in 1941. Like the earlier (nonprogrammed) calculators, Z1 (mechanical) and Z2 (electromechanical), constructed by Zuse, it did not survive the war. An improved machine, the Z4, was completed by 1945. Despite the lack of a conditional branch mechanism, it was demonstrated as Turing-complete (i.e. having power equivalent to a Turing machine) by Raúl Rojas in 1998.