Koy-Krylgan-kala was a powerful well-fortified fortress with several defensive walls, which were eventually destroyed and it was available to notice them only in a small areas. Such fortifications are characteristic of all the monuments of antiquity and the early Middle Ages of Khorezm. The earliest finds date back to the 4th-3rd centuries. BC. e.
The cult structure, in the center of which is a round two-story building, with a diameter of 44.5 m, surrounded by a defensive wall with nine towers.
The design of the building and the location of the windows allowed the scientists to reliably establish that the construction of the structure was specifically aimed to use this object for astrology and for the observation of the starry sky. The assumption that the star Fomalhaut, which is one of the brightest and most revered stars, was also indirectly confirmed by the symbol that the temple is dedicated to.
Probably the construction of the temple is somehow connected with the cult of water in ancient Khorezm, since the name of the star - Fomalhaut in Arabic means "the end of the water in the mouth of South Pisces".