I had to give this bread its own post. It's called lavash, and it's become the only type of bread I'm eating. The lovely loaf pictured above was the freshest I've had yet: I literally saw the baker pull it out of the oven, put it in a bag, and then hand it to me. I didn't quite understand how complicated it would be to explain this bread until I started writing this post. "Lavash", according to Wikipedia and UNESCO, officially refers to a type of unleavened Armenian flatbread. That is not what is pictured above, and not what I've been eating, although you can buy a pre-packaged version of Armenian lavash in some supermarkets here. The bread you see above is commonly referred to by everyone in St. Petersburg as "lavash", even though it is not what you will see if you put "lavash" into American google. Interestingly, if you type "лаваш" into Yandex, you get images of both Armenian lavash and the other kind of lavash, the one I'm eating.
As far as I can tell from my internet research, this type of lavash is originally Georgian in origin. That said, I can't tell if most of the people who sell it fresh are Georgian by ethnicity or not. I know the two bakeries that sell fresh lavash in Pushkin are run by people who are not ethnically Russian, because I've heard the bakers speaking languages that are not Russian. That said, I haven't been able to figure out which languages specifically are being used.
Based on my own knowledge of baking, I would describe this lavash as a leavened flatbread that is thin in the middle and very puffy around the outside. It's salty and chewy, and crispy on the outside, because it's baked in an oven that people here call a "tandyr" or "tandoor" that is very similar in principle to an Indian tandoor. It's made of bricks/clay/etc and gets very very hot. The bread is baked for only a few minutes on the side of the oven, which gives it a crackly, just-short-of-charred crust while preserving a beautifully fluffy interior.
There's a bakery only about a ten or fifteen minute walk away from my dorm that sells fresh lavash. It's run by a guy named Maksim and his son, and they're both very friendly - they insisted on adding me on VKontakte, partly I think because the son wants to learn English. I think they're still both kind of confused about what on earth an American is doing buying bread from them on a regular basis, even though I've tried to explain to them that I'm teaching at the university. But they're both very nice, and they make delicious bread.