Greeks head to the ballot box in two days for a contest that may determine the fate of the world's first democracy and the future of the newest reserve currency, while roiling markets from Wellington to Wall Street.

Almost 10 million Greeks will vote for the second time in six weeks after a May 6 ballot failed to yield a government. The constitution permits a third election too. The final polls, published on June 1, showed no party set to win a majority. Exit polls will be released when voting ends at 7 p.m. in Athens, with a first official result estimate due around 9:30 p.m.

The June 17 vote will turn on whether Greeks, in a fifth year of recession, accept open-ended austerity to stay in the euro or reject the conditions of a bailout and risk the turmoil of becoming the first to exit the 17-member currency. World leaders have said they'd prefer a pro-euro result, underscoring concern over global repercussions.