SAREZ LAKE, TAJIKSTAN Found in the Pamir Mountains of Tajikstan, the lake is 55.8 km long, a few hundred metres deep and is 3,263 metres above sea level. It holds 16.074 cubic kilometres of water; water seeps out of the base of the dam at a rate similar to the rate of inflow, maintaining a near constant level. This lake did not exist until 1911, when an earthquake measuring 6.5-7.0 on the Richter scale created a landslide of 2.2 million cubic metres which in turn created a natural dam within the Murghab River. It was named the Usoi Dam after the village which was buried by the landslide. The dam is 3 kilometres long and at 567 metres high, is the tallest in the world, either natural or manmade. The dam allowed the valley to be flooded by constant rain and meltwater until the lake formed, with a volume of 16 cubic kilometres. A monitoring system was put in place on Sarez Lake and within the valleys, as there are fears a future earthquake could destroy the dam and release the water in a catastrophic flash flood. Earthquakes are not the only potential hazard however. Filtration water has created some cavities within the dam and there is a partially detached rock mass of three cubic kilometres at the edge of the lake which could create too much pressure on the dam if it fell into the water. -TEL Read more: http://erg.h17.ru/sarez/sarez.html; http://atlasobscura.com/place/sarez-lake Photo: http://www.mergili.at/worldimages/upload/2010/11/29/20101129195933-04fa0319.jpg