Hønekilden (The Hen Spring) in Sønderborg, southern Denmark, was once renowned for its pure water—so much so that, in the 1500s, Queen Dorothea had it channeled through hollowed-out tree trunks to her castle’s waterworks. Locals trusted it above all other sources for cooking. Although its outlet remains visible today behind a wrought iron gate, the water is no longer drinkable. Legends surround the spring, especially in the neighborhood, where residents claimed that local newborns weren’t brought by storks but were “found swimming in the spring.” In 1924, Widow Larsen of Sønderborg…