You might have seen a delicacy known as “century eggs” on Chinese restaurant menus or on the shelves of Asian markets and wondered, “Are those eggs really 100 years old?” (Answer: They aren’t. It actually only takes about a month to make them, using a pickling liquid made from lye, salt, and water, and then rolling the eggs in mud and wrapping them in rice husks.) In a recently excavated tomb in eastern China’s Jiangsu province, however, archaeologists found a jar filled with eggs dating all the way back to the Spring and Autumn Period (770–ca. 475 B.C.), making these incredible edibles at least 2,500 years old. Sadly, only the shells remain.