From Jerusalem the view to the east is blocked by the Mount of Olives rising some 100 m above the city. A road runs along the top of the ridge, at various points there are magnificent views over the ld City and out across the Judean desert to the Jordan Valley and the mountains of Moab.
Jesus’ familiarity with the Mount of Olives stemmed from the fact that when in Jerusalem area, he stayed with his friends at Bethany (Luke 10:38; Mark 11:11). At pilgrimage time the population of Jerusalem tripled. The cost of lodging within the city became exorbitant and the poor had to make arrangements in the surrounding villages. Thus each day he walked over the hill to the city and returned at nightfall (Luke 21:37).
One evening, seated on the slope opposite of the Temple, Jesus spoke to his disciples of the future of the city (Mark 13:3) whose lack of faith had driven him to tears (Luke 19:37, 41-4). At the bottom of the slope is the garden of Gethsemane where he was arrested a few days later (Mark 14:26-52). Luke locates the Ascension on the Mount of Olives (Acts 1: 6-12).
Christians flocked to the Mount of Olives in the Byzantine period both because of its associations with Jesus and because of the splendid view of the holy places in the city. By the C6, according to eye-witnesses, there were twenty-four churches on the mount surrounded by monasteries containing vast numbers of monks and nuns.
The concentration of cemeteries (Christian, Jewish, and Muslim) on the south-western end of the Mount of Olives and on the other side of the Kidron valley beneath the Temple walls is due to the belief that the Kidron is the valley of Jehoshaphat where humanity will assemble to be judged by God.
Source: The Holy Land by Jerome Murphy- O’Connor