I have read a lot of anecdotal accounts claiming that Marco Polo was "impressed" with fireworks he saw in Cathay, and other stories that he "brought back fire crackers" or "introduced gunpowder" to Europe. For example, on the page History of Fireworks, it says "Marco Polo is credited with bringing gunpowder to Europe in the 13th century." (without any reference). Yet, when I have read the Travels of Marco Polo (in English translation), I did not see any mentions of fireworks. At one point he says farmers heaped up bamboo stalks and set them on fire to frighten animals, but this seems to refer just to the normal crackling and popping noises bamboo makes when it is set afire in large quantities, not to actual fireworks (bamboo makes a very loud cracking sound when it is set on fire, check out this video: bamboo on fire or this one (at 5:55) bamboo popping in a fire pit).
So, did Marco Polo write about or bring back fireworks from his travels, or is that just a myth?