Noushabed, also called Oeei or Ouyim is an ancient subterranean city, built beneath the small town of Nushabad in present-day Iran.

The earliest parts of the city were constructed sometime during the Sassanid period between AD 224 to 651 and continued to be excavated during the post-Islamic era, with evidence of occupation lasting until the Qajar dynasty.

Archaeologists have discovered human remains, earthen vessels, and stone instruments from the Sassanian, Ilkhanid, and Safavid periods, suggesting almost continuous use for many centuries.

Researchers have identified three distinct levels reaching a depth of 16 metres, and a complex network of interconnected tunnels and chambers covering an area of 3.7 acres. The different levels were connected through vertical and horizontal channels that also functioned as a ventilation system allowing the free flow of air throughout the substructure.