To the south of Semnan lies Rig-e Jenn between the Great Desert and Kavir National Park. Due to high sand dunes, vast swamps, and scarcity of water, the desert challenges even the avid trekker with the most arduous hike.
The Rig Jenn (Persian: ریگ جن ‘Dune of the Jinn’) is a vast area of sand dunes in the middle of Dasht-e Kavir, Iran's central desert in the border region of the Semnan and Isfahan provinces. It was not travelled by the old caravan travellers, who believed it is a place where evil spirits live. Even today some in the neighbouring towns and villages believe this. Sven Hedin, the famous desert explorer avoided this area in his 1900s explorations to Iranian deserts.