Greece has until midnight to pay $1.8 billion in debt to the International Monetary Fund. It’s expected to default. The country shuttered banks this week, and July 5, will hold a national referendum on whether to accept austerity demands from creditors. On Monday, world markets responded to the growing uncertainty, and U.S. stocks took their worst plunge of the year. As Greece enters this desperate chapter in its financial saga, thousands of miles away the island of Puerto Rico announces it cannot pay its own more than $70 billion in debt. We look at the troubled economies of Greece and Puerto Rico.