Great Kyz Kala, fortified structure located in the ancient oasis city of Merv, near the modern-day city of Mary, Turkmenistan. It is believed to have been built between the 6th and 8th centuries CE.
The Great Kyz Kala is an awe-inspiring and dramatic mud-brick structure. It comprises a rectangular earthen mound with sloping sides containing a series of rooms. Massive, corrugated external walls rise dramatically from the mound and enclose the rooms of an upper story and parapet. Enough of the interior survives to suggest there were at least 16 rooms built around a central space. Each corrugation is half-octagonal with a diameter of 4.3 feet (1.3 meters) and rises from a pointed base to form a pointed top. The walls are 6.5 feet (2 meters) thick and gently taper toward the top; they survive to a height of nearly 40 feet (12 meters).
The Great Kyz Kala stands adjacent to a smaller monument—the Little Kyz Kala—that is also made from mud brick and shares a similar corrugated construction. The larger of the two is the best surviving example of a köshk, a type of fortified structure found in Central Asia. The buildings perhaps served as residences for the wealthy and powerful. Their architecture is ideally suited to a hot, arid climate, with life based around a shaded central space that is protected from the extremes of weather by thick, enclosing mud-brick walls.
The fact that this abandoned mud-brick structure, retained without its protecting roof and without any regular maintenance, survived relatively unscathed from a period in which the majority of buildings have been lost is astounding. In 1999 the whole of Merv was designated a UNESCO World Heritage site.