Well, it’s, like, hollow.
This guy wasn’t a rocket scientest, he had fire, a rock, maybe a stick.
Yeah, I know “pita bread” is redundant.
From The Oxford Companion to Food by Alan Davidson:
Pita bread is leavened by yeast, and shaped by hand, much like a tortilla. It is left to rest before baking, where it forms a “skin” on the outside. When baked, the inside puffs, leaving the bread hollow inside. It wasn’t necessarily invented by someone, because it was originally used as a flat bread–it was just that someone figured out you could open it and stuff it. Pita, in its more original form, is usually torn into pieces, and used as a scooping utensil for food.