On a sad August 15 in 1971, President Richard Nixon removed the last vestiges of the once-great bulwark of capitalism, America’s adherence to the international gold standard, ending convertibility of the United States dollar into gold by foreign investors. The dollar has remained fiat money ever since, but did not succeed in retaining its previous value.
But then, the dollar under the previous quasi-gold, Bretton-Woods Agreement wasn’t stable either, which is why Nixon had to close the gold window.