The worlds first computer located at Bletchley Park (no it wasn't American) has just become operational again after a 16 year refurbishment. Nicknamed 'Colossus' the machine made possible the the breaking of the German 'enigma' codes and thus made a major contribution to the war effort.
Another bit of wartime history saved!....Ian
Sorry, gents, the oldest known computer is the "Antikithera mechanism" dating from (I think) the third or fourth century BC. In any event, the "Babbage difference engine" from the early 19th century would certainly qualify as an earlier computer than anything in the twentieth century.
Insert 'modern' between first and computer in my original posting. Personally I preferred the contra rotating, steam activated, child thrashing machine to the Babbage effort,..far more entertaining....and you could have a nice cup of tea while the offspring were disciplined. ...Ian
Also Babbage never completed one of his machines. The worlds first programmable, digital, electronic computer.. 'Colossus' was operational by the end of 1943...Ian