The Dir Gachin Caravanserai (also Ghasre Gach or Qal’eh Dir or Kord Shir Fort) is a caravanserai is a Samanid and Safavid era caravanserai located near Rey , in Tehran province , Iran .
Dir Gachin caravanserai was registered in national index in 2003 by the Iranian Cultural Heritage Organization as mother of Iran caravanserais .
The caravanserai has six towers (four towers at the corners and two semicircular towers on either side of the entrance). The foundation of the caravanserai belongs to a fire temple of Sassanid era that has been repurposed to caravanserai in Safavid era. The total area is 12000 square meters with a substructure of 8000 square meters .