Origin of Chinese firecrackers.
There's one old Chinese saying, that in ancient times, on the eve of new year, a ferocious monster called NIAN would appear and hurt villagers. The monster has one weekness, it fears blares and other big sounds. So, in order to drive NIAN away, each family fires the firecrackers to make blares on the new year eve. Year by year after that, it became a tradition in Chinese new year, and till now, you can see or hear the firecrackers or fireworks during Chinese Spring Festival.