Figure 11: The archaeology starts right below the surface at Merv. Here a trench (originally cut for agricultural drainage in the 1960s) exposes a complex sequence of Islamic streets. Intact street surfaces and walls survive only 30-50mm below the modern surface. Most of the area of the abandoned cities was not suitable for modern agriculture, so there is little or no damage, or subsequent reworking, and erosion/collapse deposits seal well preserved stratigraphy.