Here's a comprehensive summary of the Wikipedia article on Bublik:

Bublik is a traditional Eastern European ring-shaped bread roll, similar to a Polish bagel, made from yeast-leavened wheat dough that is briefly boiled before baking. Its name derives from a Proto-Slavic word meaning "bubble," reflecting its characteristic shape. Generally drier and chewier than a bagel, the bublik has smaller variants like the baranka and the hard, cracker-like sushka.

The concept of these boiled rings has a rich history; the first known mention of a similar bagel dates to Kraków in 1610, which then spread and evolved into the bublik in Ukraine. The term "bublik" itself appeared in Russian texts by the 18th century. Meanwhile, the baranka was documented in Russian sources from the 17th century, with Valday becoming a famed center for its production. Historically, towns like Belarusian Smarhon' were renowned for their obwarzanki (a type of baranka), even having a legendary "Bear Academy" associated with them, highlighting their deep cultural roots and widespread popularity across the region.