Photo of the first "computer bug": A Moth (1947)
Wikipedia: While Grace Hopper was working on a Mark II Computer at Harvard University in 1947, her associates discovered a moth that was stuck in a relay; the moth impeded the operation of the relay. While neither Hopper nor her crew mentioned the phrase "debugging" in their logs, the case was held as an instance of literal "debugging." For many years, the term bug had been in use in engineering. The remains of the moth can be found in the group's log book at the Smithsonian Institution's National Museum of American History in Washington, D.C.