The Kidron Valley (classical transliteration, Cedron, from Hebrew: נחל קדרון, Naḥal Qidron, literally Qidron River; also Qidron Valley; Arabic: وادي الجوز‎, Wadi el-Joz, 'Valley of the Walnut', for the upper segment near the Temple Mount, and Wadi en-Nar, 'Fire Valley', for the rest of it, with at least the segment at Mar Saba monastery also known in the 19th century as Wadi er-Rahib, 'Monk's Valley') is the valley originating slightly northeast of the Old City of Jerusalem, which then separates the Temple Mount from the Mount of Olives. It continues in a general south-easterly direction through the Judean desert in the West Bank, reaching the Dead Sea near the settlement of Ovnat, and descending 4,000 feet (1,200 m) along its 20-mile (32 km) course. The ancient Mar Saba ('Saint Sabbas') monastery is located in the lower part of the valley. In its upper part, the neighbourhood of Wadi al-Joz bears the valley's Arabic name. The settlement Kedar, located on a ridge above the valley, is named after the valley's Hebrew name. The Hebrew Bible calls the upper course Emek Yehoshafat, the "Valley of Josaphat". It appears in Jewish eschatologic prophecies, which include the return of Elijah, followed by the arrival of the Messiah, and the War of Gog and Magog and Judgment Day. The upper Kidron Valley holds Jerusalem's most important cemetery from the First Temple period, the Silwan necropolis, assumed to have been used by the highest-ranking officials residing in the city, with rock-cut tombs dating between the 9th and 7th centuries BCE. The upper Kidron Valley segment north of the Old City was one of the main burial grounds of Jerusalem in the Second Temple period, where hundreds of tombs have survived until today, while the segment east of, and opposite the Temple Mount, boasts several excellently preserved monumental tombs from the same period. Several of the Second Temple period tombs were also used later in time, either as burial or as shelters for hermits and monks of the large monastic communities which inhabited the Kidron Valley during the Byzantine Empire period (4th-7th century). The ancient tombs in this area attracted the attention of ancient travelers, most notably Benjamin of Tudela. A source of confusion is the fact that the modern name "Kidron Valley" (Nahal Kidron in Hebrew) applies to the entire length of a long wadi, which starts north of the Old City of Jerusalem and ends at the Dead Sea, while the biblical names Nahal Kidron, Emek Yehoshafat, King’s Valley etc. might refer to certain parts of this valley located in the immediate vicinity of ancient Jerusalem, but not to the entire wadi, and certainly not to the long segment crossing the Judean desert. Similarly, in Arabic every more substantial wadi has many names, each applied to a certain distinct segment of its course.