At its height, during the hyperinflation period in the Weimar Republic of Germany in the early 1920s, it took an astronomical number of German Marks to buy a single U.S. dollar. The exchange rate became so extreme that it's difficult to pinpoint an exact number, but it reached trillions of Marks to one U.S. dollar. This hyperinflation was a result of economic instability and the excessive printing of currency, and it had devastating effects on the German economy.