1944
Bretton Woods
The post-war dollar is defined against gold at $35 for official holders. Citizens do not get that window.

Bretton Woods was negotiated in 1944 at Bretton Woods, New Hampshire. Member currencies were pegged to the US dollar. The dollar was defined against gold at $35 a troy ounce for official convertibility.
Ordinary people in the United States did not redeem paper at the Treasury. The official window that remained was closed on 15 August 1971.