Aly Song / Reuters

Basins and buckets of boys' urine are collected from primary school toilets in Chinese city of Dongyang. It is the key ingredient in "virgin boy eggs," a local tradition of soaking and cooking eggs in the urine of young boys, preferably below the age of 10. There is no good explanation for why it has to be boys' urine, just that it has been so for centuries. Locals claim that the eggs have miraculous health properties.