The document discusses the evolution of the international monetary system over time. It describes several historical exchange rate regimes: (1) the classical gold standard before 1914 where currencies were pegged to gold; (2) the interwar period from 1914-1944 of fluctuating exchange rates; (3) the Bretton Woods system from 1944-1973 where the US dollar was pegged to gold and other currencies were pegged to the dollar. The Bretton Woods system collapsed in the 1970s and was replaced by (4) a system of floating exchange rates. More recently, the European Union established (5) a single currency, the euro, for many member states.