The Mount of Olives is a two-mile long ridge, or foot hill, with three summits on it. Just to the east of the Mount of Olives is the wilderness (i.e., desert) that leads down to Jericho and the Jordan Valley. It is named after the groves of olive trees that grew there in the Old and New Testament times.

David ascended the Mount of Olives when he fled from his son Absalom (2 Samuel 15:30), and Solomon built temples for foreign gods there on what is called the “Hill of Corruption” in 2 Kings 23:13.

Details of several of Jesus’ activities on the Mount of Olives are recorded in the gospels. This has led to numerous churches being built on these “holy” sites from the time of the Byzantine Empire in the early days of the church.

When Jesus was in Jerusalem he often stayed in Bethany, a village on the east side of the Mount of Olives, about a two-mile walk southwest of Jerusalem. The walk from Jerusalem to Bethany took Jesus through Gethsemane and straight up to the summit of the Mount of Olives (then along the ridge), which is today a modern road to Bethphage. Following another ridge, the road then leads into Bethany.

It is believed that the Jewish Messiah will appear on the Mount of Olives. This belief has led centuries of Jews dating back to the Old Testament to place their graves here.

On that day his feet will stand on the Mount of Olives, east of Jerusalem, and the Mount of Olives will be split in two from east to west, forming a great valley. - Zechariah 14:4

The glory of the Lord went up from within the city and stopped above the mountain east of it. - Ezekiel 11:23

Then the man brought me to the gate facing east, and I saw the glory of the God of Israel coming from the east. - Ezekiel 43:1, 2

Jesus seemed to accept this teaching and testified to it by ascending back into heaven from the Mount of Olives. His ascension was followed by the confirming statement of the angels that Jesus would return the same way he left.

When he had led them out to the vicinity of Bethany, he lifted up his hands and blessed them. While he was blessing them, he left them and was taken up into heaven. - Luke 24:50

After he said this, he was taken up before their very eyes, and a cloud hid him from their sight. They were looking intently up into the sky as he was going, when suddenly to men dressed in white stood beside them. “Men of Galilee,” they said, “why do you stand here looking into the sky? This same Jesus, who has been taken from you into heaven, will come back in the same way you have seen him go into heaven.” Then they returned to Jerusalem from the hill called the Mount of Olives. - Acts 1:9-12

Considering
1) the support of Old Testament prophecy,
2) the confirmation of Jesus by his ascension, and
3) the words of the angels, it is clear that Jesus, the Messiah, will return to the Mount of Olives and enter the new Temple in Jerusalem.

The third summit is covered with Jewish Graves because of verses like Zechariah 14:4 and Ezekiel 43:1-2 that indicate the Messiah will appear on the Mount of Olives.