Geok Gumbez (blue dome), tract in the desert zone 70 km north of Merv. There are three medieval mausoleums located in, representing the traditional type of single-chamber portal-domed tomb of the North-Khorosan architectural school. They form an ensemble of extended linearly posts. The most significant of them has on main facade a portal with lancet arch, the rest of the facades are decorated with narrow wall niches. The dome was faced with blue glazed bricks, which later fell off. The other two mausoleums are worse preserved.