Century egg, also known as preserved egg, hundred-year egg, thousand-year egg, and thousand-year-old egg, is a Chinese cuisine ingredient made by preserving duck, chicken or quail eggs in mixture of clay, ash, salt, lime, and rice straw for several weeks to several months, depending on the method of processing. After the process is completed, the yolk becomes a dark green, cream-like substance with a strong odor of sulfur and ammonia, while the white becomes a dark brown, transparent jelly with little flavor or taste. The transforming agent in century egg is its alkaline material, which gradually raises the pH of egg from around 9 to 12 or more. This chemical process breaks down some of the complex, flavorless proteins and fats, which produces a variety of smaller flavorful compounds.
Myth
According to a persistent myth, century eggs are or once were prepared by soaking eggs in horse urine. The myth may arise from the fact that significant quantities of ammonia are produced through the bacterial action on urea which changes the pH of urine from acidic to basic.(don't worry guys,it's just a myth!)
Yum yum! I love this egg and i prefer to eat it on its own XD.
I can't really eat it without congee, or it'll taste like.. metal spoons XD but with congee, it's amazinggg
My mom used to force me to eat it with porridge. 
