Artemis killed Niobe's daughters and Apollo killed Niobe's sons as they practiced athletics, with the last begging for his life. The bodies of her children lay for nine days unburied, for Zeus had changed the people to stone; on the tenth day they were buried by the gods. Apollo and Artemis used poisoned arrows to kill them, though according to some versions at least one Niobid was spared, (usually Meliboea). Amphion, at the sight of his dead sons, either killed himself or was killed by Apollo for swearing revenge. A devastated Niobe fled to Mount Sipylus (Spil Mount) of Lydia in Anatolia and was turned into a stone waterfall as she wept unceasingly. Spil Mount has a natural rock formation resembling a female face claimed to be Niobe, not to be confused with a sculpture carved into the rock-face of nearby crag Coddinus, north of Spil Mount, probably representing Cybele and attributed by the locals to Broteas, the ugly brother of Niobe. The rock formation is also known as the "Weeping Stone", as the stone is said to have wept tears during the summer. The rock appears to weep because it is porous limestone and rainwater seeps through the pores. 