Underground cities are dense, complex and wide structures identical to narrow corridors and have rooms in small dimensions.
The underground city of Nushabad in Kashan, Isfahan province, is three-story. The first floor is built at a depth of three meters and the third floor is at a depth of 16 meters.All spaces are created by delicate and subtle digging in the underground and include corridors with a height of 180 cm and in some parts to 90 cm with different widths and rooms with different sizes can be seen on both sides. The end of each corridor leads to another. The floors of this city are linked by vertical and horizontal channels. In addition to these channels, there are large rocks identical to that of the grinding mills. When taking shelter in the lower floors, the opening of the channel were closed with these rocks.