In 1914, the exchange rate of the German mark to the American dollar was about 4.2 to one. Nine years later, it was 4.2 trillion to one.

The out-of-control inflation began somewhat mildly during World War I, as the German government printed unbacked currency and borrowed money to finance military expenditures. The strategy was to eventually pay off the debts by seizing resource-rich territories and imposing reparations on the vanquished Allies.

But then Germany lost the war and ended up with massive debts and reparations to the Allies to be paid under the Treaty of Versailles.

Inflation crept up slowly at first, before accelerating rapidly in late 1922. The exchange rate ballooned from 2,000 marks per dollar to 20,000 to a million and beyond in just a few months, riding on a growing wave of economic panic and mistrust.