The euro is in trouble, and this could get very ugly for the world economy.

The ongoing financial crisis in Greece, which has lasted now for five years, took a very dramatic turn as the European Union bailout is set to expire tomorrow. The long and the short of it is that Greece is in debt. A lot of debt. The New York Times did a comprehensive piece on why the Greeks are in this predicament.

Greece became the epicenter of Europe’s debt crisis after Wall Street imploded in 2008. With global financial markets still reeling, Greece announced in October 2009 that it had been understating its deficit figures for years, raising alarms about the soundness of Greek finances.

Suddenly, Greece was shut out from borrowing in the financial markets. By the spring of 2010, it was veering toward bankruptcy, which threatened to set off a new financial crisis.

To avert calamity, the so-called troika — the I.M.F., the European Central Bank and the European Commission — issued the first of two international bailouts for Greece, which would eventually total more than 240 billion euros, or about $264 billion at today’s exchange rates.

The bailouts came with conditions. Lenders imposed harsh austerity terms, requiring deep budget cuts and steep tax increases. They also required Greece to overhaul its economy by streamlining the government, ending tax evasion and making Greece an easier place to do business.

The money was supposed to buy Greece time to stabilize its finances and quell market fears that the euro union itself could break up. While it has helped, Greece’s economic problems haven’t gone away. The economy has shrunk by a quarter in five years, and unemployment is above 25 percent.

The bailout money mainly goes toward paying off Greece’s international loans, rather than making its way into the economy. And the government still has a staggering debt load that it cannot begin to pay down unless a recovery takes hold.

And that recovery has not happened. The Greek economy is largely dependent on tourism.