Azelli vessels, or Azellenov, or Venetian or Venetian vessels, are vessels made of unbreakable glass discovered in 1928 in Venice, created in the 16th century. They allow us to judge the creation of unprecedented thick-walled vessels with very low fragility and an extremely smooth surface. Having no analogues, they were identified as products of the Tuscan glass-making center in the second half of the 16th century. They are classified as inventions of the 16th century for other reasons, namely: they represented the last stage in the history of blown glass technology in Europe; their authors were never mentioned in written sources that preceded their creation, which indicates the special significance of the blowing technique for the glassmaker of that time; they are created without a specific technical purpose (unlike known other products).