To put it simply, the European debt crisis is actually a crisis triggered by the chain break of some euro zone countries through the issuance of government bonds. More specifically, when the old national debt expired, these countries encountered financing difficulties when issuing new national debt. It may be that no one cares about the newly-increased national debt, or that the newly-increased debt interest has risen sharply, which is beyond the government's capacity. At the same time, because of excessive borrowing, the government exceeded its normal income level and could not make ends meet, which became a sovereign debt crisis. "Buying" prosperity through government borrowing is a common economic development model adopted by western developed countries since the Great Depression in 1930s. It is characterized by taking government expenditure as a booster to promote economic growth, paying off old debts by issuing new debts, maintaining deficit finance for a long time, establishing a modern social welfare security system, alleviating social contradictions and realizing long-term economic growth and prosperity. However, with the passage of time, the scale of government deficit is getting bigger and bigger, and the debt level is getting higher and higher, which eventually leads to the concentrated outbreak of the crisis. If the euro zone is regarded as a country, the sovereign debt of the euro zone countries becomes domestic debt. Usually, it doesn't matter how much domestic debt a country has, because the country is a country of citizens, and the country borrows money from citizens, just like the money in a person's left pocket goes into his pocket, which has no effect on a country's income. The way to repay domestic debt is to develop the economy, increase taxes, or, as everyone wishes, the central bank will print money to solve it. When a government has the right to issue currency, it can issue new currency to pay off its local currency debt, that is, domestic debt. At this time, the government will not default on domestic debt, which is why sovereign bonds denominated in local currency enjoy the highest credit rating in China. However, individual countries in the euro zone do not have the conditions to issue additional euro hedging bonds, and there is no "lender of last resort". At the beginning of the establishment of the euro zone, monetary policy was unified, but there was no unified fiscal policy (because fiscal power is still regarded as a matter within the sovereignty of all countries). This dual structure was questioned from the beginning, but its harmfulness did not really appear until the debt crisis broke out. Because there is no unified "central" financial support in the euro zone, and the European Central Bank insists on monetary stability as its primary task, it is unwilling to adopt the "quantitative easing" policy like the United States. When there is a debt crisis in the euro zone countries such as Greece, it can only rely on its own finances as debt repayment guarantee. Once their credit is questioned, they will inevitably be unable to restore market confidence on their own, and it is easy to fall into crisis. The bucket of Danes (the bucket of Danaides). This is a Greek legend: the Egyptian king has two sons, the eldest son has 50 sons, and the second son has 50 beautiful daughters, which are called the Dana Ides sisters. The eldest son forced the second son to marry 50 beautiful daughters to his 50 sons. After pretending to agree, the second son told his daughters to kill their groom on their wedding night. All his 49 daughters complied, but the youngest daughter couldn't bear it (it must be true love), and the king's eldest son died of grief after learning the news. The only groom who didn't die eventually killed his uncle and his 49 daughters and punished them for working in hell and pouring water into a bottomless bucket endlessly, so Danaydes' sister bucket means endless, futile work or "bottomless pit". In order to prepare for the centennial Olympic Games, Greece mobilized the strength of the whole country and made every effort to show the world a wonderful Olympic ceremony, but what it paid was an explosive budget overrun and a bottomless debt pit. After the European debt crisis detonated from Greece, it is "appropriate" to describe its birthplace with this fairy tale, which is extremely ironic.