The Venetian guild of glass makers guarded its trade secrets more heavily than any other known art guild in history. And it is a very long history - you can trace it back to 9th century Roman, Asian and Byzantine roots. Venice's unique location at the crossroads of major trade routes made it a perfect place for exchange of ideas, formation of new art traditions and the blending of old ones into something new and exciting. It is interesting that a simple decree in 1291 that called for moving of all furnaces away from...

"Murano glass is only made in Murano." 
This statement was written on a poster, greeting visitors in the Venetian airport. It summarized a centuries-long struggle to keep this Italian treasure intact, protecting it from global mass-consumption, which often confuses pretentious counterfeit objects for the real thing. It turns out that chemistry is on the Venetians' side in this struggle.