A Serbian police officer inspects a dam of sandbags by the bank of the Sava river in Sremska Mitrovica, 90 kilometers west of Belgrade, Serbia, Thursday, May 22, 2014. Serbia, Bosnia and Croatia have been hit by the worst flooding in more than 100 years, forcing half a million people out of their homes and leading to more than three dozen deaths. (AP Photo/Darko Vojinovic)