Erk Kala is an ancient site located in the historic city of Mary in Turkmenistan. It is one of the earliest and most important archaeological sites in the region, reflecting the rich history of human civilization in Central Asia. Erk Kala is considered the oldest part of the ancient city of Merv, which has been recognized as a UNESCO World Heritage Site. This site is believed to have been established in the 7th century BC and functioned as an urban center until the 3rd century AD. The impressive ruins of Erk Kala include a fortified citadel with formidable walls that once stood over 20 meters high, encompassing an area of roughly 12 hectares. Visitors can explore the remnants of residential and administrative buildings, fire temples associated with Zoroastrianism, and the complex irrigation systems that hint at the advanced urban planning of the era. The site conveys a sense of grandeur and mystery, offering a rare glimpse into the historical development of urbanization, trade, and culture in the Parthian and Sassanian periods.