Lying Between the Eastern Part of the Walled Old City of Jerusalem and the Templ Mount, and Mount of Olives at the Eastern Side Of Jerusalem is a large valley that stretches for 32 kilometers (20 miles) from Jerusalem to the Judean Desert and then to near the Dead Sea. This valley is known as the kidron valley or Valley of Jehosofhat, which is the biblical site where the resurrection of the dead will begin when the Messiah comes. Legend has it that a miraculous bridge will span the valley at the end of time, over which the righteous will pass on their way to the Temple Mount. among the sights at the Valley is the Tomb of The Virgin Mary, the Church of Mary Magdalene, the Church of All Nations and Garden of Gethsemane.
according to wikipedia:
The Bible calls the Valley "Valley of Jehoshaphat - Emek Yehoshafat" (Hebrew: òî÷ éäåùôèý), meaning "The valley where God will judge." In the times of the Old Testament kings, the Kidron Valley was identified with, at least in part, the King’s Garden; the kings owned land in the area. That the Kidron Valley was also known as the King’s Valley and in which Absalom set up his monumental pillar, is problematic. The Bible does not make this identification explicit, and the association can only be inferred as associated with En-rogel, which is at the lower end of the Kidron Valley.
It should be noted that not all scholars agree with the traditional view that the Kidron Valley is the location of the Valley of Jehoshaphat. Biblical commentator Adam Clarke maintains this view, claiming that the Valley of Judgment is a symbolic place. Kidron Valley was not associated with the Valley of Jehoshaphat until the 4th century AD.
A passage in the Bible mentions that God will assemble all nations in the “Valley of Jehoshaphat” (Joel Joel 3:2, Joel 3:12). Some hold that the Valley of Jehoshaphat (“Yahweh shall judge” ) refers to the valley situated between Jerusalem and the Mount of Olives to the east. It was in this valley where king Jehoshaphat is thought to have overthrown the enemies of Israel (2Chr. 2Chr. 20:26). Its identification with the Kidron Valley, which began in the fourth century, is somewhat uncertain since no actual valley of this name is known to pre-Christian antiquity.