Naryn Castle, Meybod
The Naryn Castle (In Persian: نارین قلعه) or Narin Castle is a mud-brick fort or castle in the town of Meybod, Iran. Structures like these constituted the government stronghold in some of the older (pre-Islamic) towns of central Iran. Some of these castles incorporate mud bricks of the Medes period and of the Achaemenid and Sassanid dynasties. The ruins of the structure stands 40 meters (130 ft) high from its base. Although built some 2,000 years ago, it contains what seems to be a type of plumbing system (made out of a kind of mortar  called "sarooj") which was built into its massive walls. It is also peculiarly similar in design to "Ali Qapu" palace of Isfahan; it has a terrace high on top of the structure whose circulation is provided by two helical stairwells (whose walls have caved in, making it inaccessible). The structure also has a large underground chamber (now filled by rubble), was possibly used as a prison. Four towers surround the entire compound, and a large gate furnishes access to a large courtyard. The structure seems to have been affected by numerous earthquakes throughout the ages. Some believe that the Narin  castles are descendants of ancient fire-temples; some of the castles in Narin and Meybod, in Yazd province, are also called "nareng" castles (orange castles), possibly by folk etymology. The castle at Meybod is currently under study. Yet this castle has not been faring very well. This building has been built as an old fortress with 3 different floors, each for a different class of society. Although all outer gates have been destroyed the inner castle still exists. You can still see some of the outer walls.