Greek fire, or Byzantine fire, is a closely guarded secret due to it's amazing power to resist extinguishing when set aflame. Used sparingly in early warfare, it was able to turn the tides of numerous battles both land and sea. Ancient greek fire had a number of unique features. 
- It burned on water, and, according to some interpretations, was ignited by water. In addition, as numerous writers testify, it could be extinguished only by a few substances, such as sand, which deprived it of oxygen, strong vinegar, or old urine, presumably by some sort of chemical reaction.
- It was a liquid substance, and not some sort of projectile, as verified both by descriptions and the very name "liquid fire".
- At sea, it was usually ejected from siphons, although earthenware pots or grenades filled with it or similar substances were also used.
- The discharge of Greek fire was accompanied by "thunder" and "much smoke".