Nostradamus was an astrologist from 16th century France. He made 942 poetic predictions in his book Les Propheties. In modern times some of these prophecies have been retroactively been applied to modern events such as the moon landings, the rise of Hitler and 9/11. Strangely these weren't precise enough to warn people not to go to work on September 11th in New York. In reality Nostradamus wrote a lot of vague statements that can be retroactively fitted to momentous events.
His writings were mostly in the form of Quatrians - 4-line poems - and written in medieval French. They often made little or no sense, even at the time, as he added coded terms and words from Latin, Provencal and Greek to make him seem more mysterious. Because of this any citation of his work has had to undergo several translations, often of words and phrases whose original meaning has long been lost.
Modern translations are simply re-written to make them fit modern events. For example, the line "Two steel birds will fall from the sky on the Metropolis" is often quoted to predict 9/11. Given that steel was not invented and the term coined until 1854 — nearly 200 years after Nostradamus died - it is clearly a misquote at best.