The human toll of the Syrian Civil War:
More than 2.5 million Syrians have been uprooted, the IRC says.
Of those who have had to leave their homes, about 600,000 have fled, mostly to Jordan, Turkey, Lebanon and Iraq, which border Syria.
It's a replay of the population flight out of war-torn Iraq last decade. It conjures the wrenching flight in the 1940s during the birth of Israel, also next door to Syria.
"The Middle East is once again facing a human displacement tragedy," the IRC's commission on Syrian refugees said.
Syria had a prewar population of almost 23 million, so that's more than one in ten who have had to flee their homes.