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Two hilltop towers overlook the Iranian city of Yazd, their simple cylindrical walls giving no indication of the gruesome scenes that once took place within them. The structures are known as dakhma, or towers of silence. The Zoroastrians of Yazd used these places as open burial pits, placing their deceased relatives in rows so their bodies would be feasted upon by birds of prey.

Sky burial—placing a deceased human body in an exposed location so that animals and the elements will hasten its decomposition—has long been a part of Zoroastrian tradition. According to the religion’s beliefs, a body becomes impure at death, when evil spirits, or nasu, arrive to attack the flesh and soul of the deceased. By contaminating the corpse, nasu also threaten the living. Sky burial is considered a clean death because it prevents putrefaction—birds of prey such as vultures can eat a body down to the bones in just a few hours.

At Yazd, bodies were hauled up to the towers and arranged in concentric circles with their feet pointing toward the center. Children were placed in the innermost ring, women in the next, and men in the outside ring. Once bodies had been stripped of flesh, muscle, and organs, and the skeletons bleached and weakened in the sun, the bones were placed in a central pit to break down.

When they were first built millennia ago, Yazd’s Towers of Silence were far from the bustle of the city. Development and urbanization resulted in a sprawl that skirted too close to the towers. They are no longer used for burial—Zoroastrians have adopted alternative “clean death” methods, such as burying bodies in cement-lined coffins to prevent contamination of the earth.

Though Yazd’s Towers of Silence are now relics, Zoroastrians elsewhere maintain the dakhma tradition. The Parsi Zoroastrians of India still practice sky burial—although the ritual has become more difficult to conduct in recent decades due to the dramatically diminishing vulture population. In 2012, NPR reported that Mumbai Zoroastrians have been experimenting with solar concentrators to hasten decomposition via intense heat. Vulture sanctuaries have also been proposed in order to raise more birds of prey to feast on the human dead.

Visit Atlas Obscura for more on the Zoroastrian Towers of Silence.

Visit Atlas Obscura for more on the Zoroastrian Towers of Silence.

To find out more about sky burial traditions around the world, read Meg Van Huygen’s article “Give My Body to the Birds: The Practice of Sky Burial.”