Syriza

Syriza's victory in Sunday's election marks a personal triumph for Tsipras, who served as prime minister between January and August — a tumultuous period that saw Greece's future in the 19-country eurozone come under real threat and strict banking controls imposed.

At 41, Tsipras dominates Greek politics despite a major policy U-turn that saw him go against the anti-austerity platform that swept him to power in elections in January in return for a multibillion bailout that keeps Greece in the eurozone.

They are trying to prevent Greece from holding its third national vote this year, although chances of averting the election are virtually nil.

Former Energy Minister Panagiotis Lafazanis, who heads the newly formed Popular Unity, received the maximum three-day mandate from the country's president after the head of the main opposition conservative New Democracy failed to form a government.

In 2012, financial markets were rattled by the possibility that Greeks would elect a left-wing government, default on their debts and drop the euro currency. The fears pushed the Standard & Poor's 500 stock index down nearly 10 percent that spring.

Here's how things look now: The left-wing party, Syriza, holds power in Athens. Greece actually did miss a loan payment to the International Monetary Fund late Tuesday. And the nation's future in the eurozone hinges precariously on a referendum Sunday.