Einstein's special theory of relativity was "falsified" *thousands* of times
"But there yet remains an almost ludicrous part of the story to be told. The Michelson-Morley experiment of 1887... actually did not give the result required by relativity! It admittedly substantiated its authors' claim that the relative motion of the earth and the 'ether' did not exceed a quarter of the earth's orbital velocity. But the actually observed effect was not negligible; or has, at any rate, not been proved negligible up to this day... Moreover, an effect of the same magnitude was reproduced by D. C. Miller and his collaborators in a long series of experiments extending from 1902-1926, in which they repeated the Michaelson-Morley experiment with new, more accurate apparatus, many thousands of times." -- Michael Polanyi, Personal Knowledge, p. 12, emphasis mine
Polanyi notes that when Miller announced his results... the general community of scientists simply ignored him. They were already convinced that relativity was correct, and didn't care about its "falsification." And Polanyi contends they were quite correct to take this attitude.
Is there a theory that has been more thoroughly "falsified" than Popper's idea of "falsification" as the cornerstone of science?