The 1944 Bretton Woods system was a gold-exchange standard: the US dollar was pegged to gold at $35/oz, and other currencies pegged to the dollar. Only foreign central banks could redeem dollars for gold — a crucial asymmetry.

Robert Triffin identified the built-in contradiction: the world needed dollars for trade and reserves, but supplying them required US deficits, which eventually undermined confidence in dollar-gold convertibility.

Liquidity vs. confidence: too few dollars → global liquidity crunch; too many → redemption runs.
Nixon Shock (Aug 1971): US suspended convertibility, ending Bretton Woods.
Legacy: today's fiat system inherits the reserve-currency role without the gold anchor.

Year	US gold cover of dollars	Event
1945	~55%	Post-war peak
1960	~18%	London gold pool formed
1971	~12%	Convertibility suspended