Zendan-e Soleyman
Iran · Asia

About
The Prison of Solomon (Persian: زندان سلیمان, romanized: Zendān-e Soleymān) is a hollow cone shaped hill in West Azerbaijan province, Iran. There is an 80 meters deep pit in the middle of the hill, and the entrance to the pit is roughly 65 meters in diameter.
Adapted from Wikipedia (CC BY-SA)。Photography via Wikimedia Commons.