Dremuchij (Russian: Дремучий, "dense") was a forest in Tselinoyarsk, USSR, that was located at the edge of a high cliff. The center of the area consisted of swampland inhabited by Indian Gavials. The mud within the swampland was highly viscous, making travel on foot hazardous, and as such, was often referred to as a bottomless swamp. Also known as "the untouched forest," Dremuchij had largely been unaffected by human activity by the early 1960s, and was so dense that large units were unable to penetrate it, making it a natural defense against enemy forces. Because of its defensive properties as a border area of Tselinoyarsk, it acted as one of the major reasons behind the development of the Sokolov Design Bureau and Groznyj Grad within Tselinoyarsk.