It all began with the fact that the dollar is rigidly tied to gold. The dollar became a reserve currency backed by gold. All countries naturally rushed to make deals for the bucks. In addition, storage in bucks, unlike gold, brought an additional interest income. On the one hand, gold for the dollar should be sold at a fixed price, and on the other: the volume of transactions increased, dollars, backed by gold is not enough. As a result, the dollar was detached from gold. But dollars were left and return them on the old course nobody wants. As a result, the US owes everything, and the dollar remained the currency on which everyone depends.