What do you mean? I thought the US dollar was fixed to gold between WWII and 1971:
> On 15 August 1971, the United States ended the convertibility of the US dollar to gold, effectively bringing the Bretton Woods system to an end and rendering the dollar a fiat currency
> On 15 August 1971, the United States ended the convertibility of the US dollar to gold, effectively bringing the Bretton Woods system to an end and rendering the dollar a fiat currency
https://en.wikipedia.org/wiki/Bretton_Woods_system