Chilpyk Kala, Southern Karakalpakstan, Uzbekistan
The fact that a lot of debris of Zoroastrian ossuaries (bone repositories) were found on the slopes of the hill provides a reason to believe that Chilpyk served as the "tower of silence" or dakhma. It is the name for structures where Zoroastrians used to put dead bodies before burial. After the bones were cleaned of flesh by birds of prey and dried in the sun they were buried in ceramic ossuaries. After the Arab conquest and conversion of Khorezmians to Islam Chilpyk changed its purpose. The fortress was rebuilt to be used as a guard and signal tower.