Mazandaran

The ancient manmade Espahbod Khorshid cave is located on the roadside of Firoozkooh in Mazandaran Province, northern Iran.

Dating back to the end of the Sassanid period (224–651 AD), Espahbod Khorshid was regarded as a fortified garrison and a fortress of Tabarestan later on.

Tabarestan was the name applied to Mazandaran Province by the natives of the region; although, the region was called Tabaristan from the Arab conquests to the Seljuk period.

Discovered in 1956, the cave is famous as a legendary castle with tens of rooms dug in the cave which was a residing spot during the Sassanid era.

Measuring 80x100 meters, Espahbod’s arched entrance is the largest natural one in the world portrayed as the biggest yawn in history. There is a four-story-high castle made of stones and mortar on the left side of the cave that is the masterpiece of architecture of its time.

On the right side of the cave, numerous trenches and defensive buildings were built, all of which remained firm and intact after centuries.

The remains of a cistern, several silos and numerous defensive monuments are located outside the cave.

According to chronicles, this cave was used as a shelter by Khorshid (Sun), the last ruler of Tabarestan.

Access to the cave needs special equipments and also expertise in alpinism.