First there was Israel's "separation wall"; then came Egypt's increasing fortification of its border with Gaza (including evacuation of the Egyptian side of Rafah). In the wake of the rise of ISIS, we read that "Saudi Arabia is Building a 600-Mile 'Great Wall' to Shield Itself from ISIS."
It was apparently this construction that was recently attacked by ISIS, killing several Saudi Border Guards.
"Something there is that doesn't love a wall . . ."