A mysterious plague has broken out, worldwide, almost instantly transforming humans into what appears to be zombies. They are slow in their dormant phase but when food is near they speed up, so you have both the "slow zombies" and the "fast zombies" in the same movie. Brad Pitt portrays a retired government agent who is forced to go back into service in order to save his family. They barely escape from the rooftop of a building over run by the creatures. Pitt and a team first go to Asia, as it was reported that the virus may have started there--and then it's off to Israel, which has constructed a huge wall around Jerusalem to keep out the rabid creatures.
This zombie epic is much better than I thought it would be, though I could have done without the ending monologue by Brad Pitt, which is almost as lame as the ending of I AM LEGEND. If you've enjoyed Italian Zombie movies you'll love this incarnation of the sub-genre.