Tourists pull their bags and suitcases on September 28, 2011 in the center of Athens during a 24-hour public transport strike and a 48-hour taxi strike. The head of the European Commission warned on September 28 that the debt crisis posed the biggest challenge to the EU in its history as Greece made a last-gasp pitch to secure vital bailout funds. As a team of international auditors prepared to descend on the Greek capital to determine whether Athens had made enough economic reforms to earn another eight billion euros in loans, fresh falls on European markets highlighted a general scepticism about whether the crisis could be tamed. AFP PHOTO / LOUISA GOULIAMAKI (Photo credit should read LOUISA GOULIAMAKI/AFP/Getty Images)