How did gunpowder spread from China to reshape the entire world?

The answer

Gunpowder was accidentally discovered by Chinese alchemists around the 9th century CE while searching for an elixir of life. China used it first in fireworks and fire arrows, then in early bombs and rockets. It spread westward along the Silk Road, reaching the Islamic world by the 13th century and Europe by the 14th. In Europe, gunpowder rendered castle walls and armored knights obsolete virtually overnight, dismantling feudalism and enabling the rise of centralized nation-states.