In 1923, German money was so worthless it became wallpaper and insulation!

de bene esse: literally, of well-being, morally acceptable but subject to future validation or exception

After World War 1 Germany was forced to pay $132 billion in reparations because they were blamed for starting the War. The problem was they did not have $132 billion in gold and revenue as a country to satisfy the force payment. The value of their currency plummeted and became worthless. Germans needed hundreds of dollars to buy a loaf of bread. The whole thing was ridiculous. People ended up collecting the money and using it as wallpaper to insulate their homes, because that was a more valuable use of the paper.

The country was in dire straits by 1923. They began reevaluating the situation and to find other means of currency to reboost the economy and eventually settled on the Reichsmark as their new currency and built their economy based on that currency.