Origin of Chinese New year festival

Why Chinese celebrated the Chinese New year?
According to the legend, there was a monster called "nien(year)" resembling the lion, preying on the people long time ago, probably appearing during the new moon. By chance, they found that the monster was scared of drum noise, red banners and the firecrackers, and they successfully drove off the monster on the second new moon after the Winter Solstice. From there onwards, the Chinese celebrated this new moon as the Chinese New Year which was also fixed as the beginning the Chinese lunar calender.
Therefore, the Chinese New Year is always accompanied by releasing of firecrackers, lion dance, drumming and red papers.

There was some basis of the noise scaring off the creature. Just look at the reaction of our dog when firecrackers were released, hide beneath the car for a long time, refusing to come out!