There's a castle made of salt in Iran - Apparently.
The Sheikh Barfkr castle, located in the Yazd province of Iran, was built in the 11th century using blocks of salt. The castle's walls were constructed using salt extracted from the nearby mountains, which were then carved into blocks and stacked to form the structure. The castle's unique composition has allowed it to withstand the harsh desert climate, although it has been severely damaged by earthquakes and is now largely in ruins.