Merv existed here because of water, the Merghab River. Most of this nation is covered by the Karakum Desert. Ironically, that dependence on water was used by the sons of Genghis Khan, who arrived with an army of 8,000 soldiers in 1221 A.D., were repulsed by the walls and defenders, but finally forced surrender by destroying the city's dam on the Merghab River. With no water supply, the city gates were opened to the Mongols who proceeded to kill its inhabitants. Merv's ancient glory days came to an end.
It is a relief to be heading home after 5 weeks of travel across Asia. This completes our around-the-world adventures on the 38th parallel--almost. Japan is still to come, we hope, in September. The book that will flesh out these stories about water-related water and cultural intersections along the 38th parallel will be published in autumn 2012 by U.C. Press.