Gyz Kala and Oglan Kala are impressive remnants of ancient fortresses located within the vast archaeological site of Merv in Turkmenistan. Merv is one of the oldest and best-preserved oasis-cities along the Silk Road, and it has been recognized as a UNESCO World Heritage Site. Historically, Merv was a major center of international commerce and trade, and a capital of the Islamic world. Gyz Kala, also known as the 'Maiden’s Castle,' and Oglan Kala, the 'Boy’s Castle,' are part of Merv's urban area and believed to have been built in the 6th or 7th century AD. These fortresses showcase the impressive defensive architecture of their time, with Gyz Kala having an irregularly shaped oval structure composed of high mud-brick walls that have endured for centuries. Oglan Kala, while not as well-preserved as Gyz Kala, represents an essential component of the ancient city's fortifications. The site is characterized by its unique combination of residential and defensive functions and provides insight into the urban and military planning of early civilizations in Central Asia.