The Great Sand Dune.
The Eastern Great Sand Dune (東の大砂丘, Higashi no Daisakyū, English TV: Great Sand Dune of the East) is a large, secluded sand dune located somewhere within the Land of Wind. Due to it being located within the desert, the area itself is completely surrounded by sand with the exception of a giant rock at the centre of the dune. The rock itself contains a small, cave-like opening, with which Orochimaru had used as his hideout upon leaving Akatsuki. The location also features a number of hidden traps such as desert snakes, which alerted him when Akatsuki came. According to Sasori, it is an area villagers from Sunagakure don't go near.