Kidron Valley

Kidron Valley is the modern name of the valley originating slightly northeast of the Old City of Jerusalem, which then separates the Temple Mount from the Mount of Olives, and ending at the Dead Sea. Beyond Jerusalem 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 along its 20-mile course.

In ancient Hebrew sources, as well as in Arabic, different segments of the valley bear different names. Arabic names include وادي الجوز, Wadi el-Joz, 'Valley of the Walnut', but possibly a shortening of "Valley of Josaphat", 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 the ancient Mar Saba monastery also known in the 19th century as Wadi er-Rahib, 'Monk's Valley'.

Source: Wikipedia