Samples of shale rocks recovered in central and eastern Poland are displayed at the State Geological Institute in Warsaw, Poland on Wednesday, March 21, 2012 during the presentation of the institute's report that estimated the nation's recoverable shale gas reserves at between 346 and 768 billion cubic meters, below expectations. Poland is hoping that unconventional gas will help to break its dependence on Russian gas imports. (AP Photo/Czarek Sokolowski)