Section 2 of Preface: The Fulfillment of the Prophecy of Daniel and World Events Near the Time of the Writing of The Revelation:

Under the Roman empire, Christians suffered immeasurable persecution at the hand of the emperor Nero in the A.D. 60's. 

As Jesus had predicted in Matthew 24 (referring to Daniel's Old Testament prophecy), the destruction and abomination are about to unfold:

The Roman Siege of Jerusalem:

After Nero's rule of thirteen years, Galba and Otho occupied a year and a half, and then Vespasian, who had distinguished himself in the campaigns against the Jews, was proclaimed emperor while still in Judea. He immediately set out for Rome, entrusting to his son Titus the war against the Jews.

The violent insurrection:

The rebuilding and beautification of the temple in Jerusalem, begun by Herod the Great in 20 B.C., was finally completed in A.D. 64 -- 60 years after Herod's death. A mere two years later, the Zealots, a fanatical Jewish sect, instigated a violent insurrection against Rome. In A.D. 70 the revolt was crushed, and Jerusalem and the temple were destroyed.⁽¹⁾

The church in Jerusalem (Christians) ordered to leave:

Before the war began, members of the Jerusalem church were ordered by a revelation to leave Jerusalem and settle in a city of Perea called Pella. Here they migrated from Jerusalem...⁽²⁾ (Note:  The Christians who remembered Jesus' instructions to leave Jerusalem --Matthew 24:1-3, 15-21-- were spared from the destruction).

Sword, famine and other forms of death:

Those who wish may trace precisely from Josephus' history the disasters that overwhelmed the entire nation, especially how the residents of Judea were driven to the limits of suffering; how many thousands of men, women and children died by the sword, famine, and countless other forms of death; how many famous Jewish cities endured horrors under siege, and in particular the terrors of those who fled for refuge to Jerusalem as an "impregnable fortress." ⁽²⁾

Utterly destroyed by fire:

They can study (from Josephus' history) all the details of the entire war and how in the end the abomination of desolation, declared by the prophets, was set up in the very temple of God, celebrated of old, when it was utterly destroyed by fire. ⁽²⁾

Deep silence and a lethal darkness:

Those who stayed in Jerusalem were now unable to leave the city. The Jews lost all hope of survival, and the famine became even worse, devouring house after house, family after family. The homes were filled with women and children thus destroyed, the alleys with corpses of old men. Young men, swelling with hunger, haunted the marketplace like ghosts and fell dead in their tracks. The sick could not bury their relatives, while those still fit evaded the task due to the numbers of the dead and their own uncertain fate, for many fell dead while burying others, and many set out for their own graves while they were still able. There was not weeping or wailing as hunger conquered emotion, and those who were dying looked with dry eyes on those already dead. Deep silence and a lethal darkness shrouded the city.⁽²⁾

The fate of millions:

In estimating the total number of lives lost, the historian (Josephus) says that 1.1 million died by famine and the sword, that the partisans and terrorists informed against each other after the city's capture (by Rome) and were executed, and that the tallest and the handsomest of the youths were saved for the triumphal parade. Of the rest, those over seventeen years of age were sent as prisoners to hard labor in Egypt, and even more were divided among the provinces to be killed in the theaters by sword or wild beasts. Those under seventeen were sold into slavery and the number of these alone was ninety thousand.⁽²⁾

Those that fled to Masada:

The last fortress of the revolutionaries (about 1000 men, women and children) was Masada, a massive, flat-topped rock near the Dead Sea. Herod had built palaces on Masada, choosing the location in large part because it was easy to defend, with steep slopes on all sides.⁽¹⁾

The siege of Masada:

The Roman army laid siege to Masada in A.D. 70. They built a camp, the remains of which are still visible, and spent several frustrating years attacking the mountain with catapults and other war machines. Finally the Romans decided on the only strategy left: they constructed a massive earthen ramp up the side of the mountain until they were able to walk to the top.⁽¹⁾

When the Romans finally broke through, only two women and five children were still alive, the rest having committed suicide rather than surrender.⁽¹⁾

⁽¹⁾ Source: Halley's Bible Handbook

⁽²⁾ Source: Eusebius - The Church History (Eusebius of Caesarea - A.D. 260-339- was the first to undertake the task of tracing the rise of Christianity during its crucial first three centuries from Christ to Constantine.)

Question:

According to the above historical accounts, the Roman siege against the Christians and Jews in Jerusalem and other areas ended in A.D. 70 with the destruction of Jerusalem and what structure within Jerusalem?