If you're looking for the most famous food in Tianjin, look no further than Goubuli. The restaurant is now a global sensation, with locations around China and the world, but it got its start here in the late 1880s. The dish itself is familiar: a steamed, meat-stuffed bun (baozi, 包子). The brand is what you're after here. (During the Olympics, the brand adopted an English name, Go Believe, as well.)
While all of the Goubuli shops now sell a wide variety of baozi and other dishes, the classic thing to order is a juicy, pork-filled bun flavored with soy sauce, ginger, scallions, and sesame oil. Count the pleats in the top of your bun—there will never be fewer than 18.
Reviewers debate whether Goubuli is still worth the hype. Personally, I think you'll never know unless you taste them.