The Judean Desert, located in the eastern edge of central Israel, is an array of hills and canyons, falling from the heights of around 1,000 meters in the Judean Mountains, to the Dead Sea which is, at -421 meters below sea level, the lowest place on earth.
The Judean Desert has an average annual rainfall of 47mm. This is due to the fact that the rains in Israel, which comes from the Mediterranean Sea, are blocked by the Judean mountains, creating a rainshadow desert over the eastern slopes of the mountains (the Judean desert), while the western slopes (the Shephelah) receive an average annual rainfall of about 500mm. Because of that, the Judean desert contains a relatively large amount of oases, which are fed by the groudwater from the western slopes of the Judean mountains.
Though hostile and arid, the Judean desert was settled since before recorded history. Jericho, which was founded over 12,000 years ago (around 9,000 BCE), is one of the oldest continuously-inhabited cities in the world, and it is the first city in the world that had walls built to protect it. Another notable place is Ein Gedi, a large oasis that had cities built around it for over 6,000 years.
The Judean desert played an important role in the jewish kingdoms in Israel during the biblical times, and also during the greek and roman times. Because of its' rough terrain and climate, The Judean desert was known as a hiding place for refugees and rebels. King David fled to the Judean desert with his soldiers after king Saul ordered to have him killed. During the greek and roman times, the Hasmonean dynasty and the roman client king Herod the Great built and fortified many forts, strongholds and even palaces in the Judean desert, most famously, Masada. During the Roman-Jewish wars, the jewish rebels fled to the Judean desert and fortified in the strongholds there. The last free standing jewish stronghold in jewish history, prior to the establishment of the modern state of Israel, was Masada.