This image was taken as astronauts aboard the International Space Station flew over one of the great mountain ranges of central Asia, the Tien Shan. Lake Issyk Kul (image lower left--182 km long) is among the largest lakes in the world; second largest mountain lake behind Lake Titicaca in South America. The lighter blue tone of the Kapchagay reservoir (image top right) reveals that it is much shallower than the dark blue Issyk Kul. Between the lakes, Almaty, capital city of Kazakhstan, is barely visible on the lower flanks of the mountains. Compared with the atmospheric clarity over the region, a dull gray smog blanket marks the city on this winter day.
Lake Issyk Kul is a Ramsar Wetland site of globally significant biodiversity and forms part of the Issyk-Kul Biosphere Reserve. It has wider historical interest as a way station on one branch of the Silk Road, the ancient overland trade route between Europe and the Far East. Significant ruins dot the shores. Some historians have argued that this part of central Asia was the point of origin for the Black Death that then moved along the Silk Road to Europe and Asia during the early and mid-14th century.