Migrating gray cranes fly over the Hula Lakes on November 30, 2011 in in northern Israel. The tens of thousands of cranes which break their southward migration to and from Africa from as far away as Siberia spend a few days at the lakes feeding in farmers' fields and gathering their strength for their onward journeys. An estimated 500 million birds fly over Israel twice a year in their annual migrations. (Photo by Uriel Sinai/Getty Images)