“And as some were speaking about the temple, that it was adorned with beautiful stones and consecrated offerings, He said, As for these things which you are looking at, the days will come in which there will not be left a stone upon a stone which will not be thrown down.” (Luke 21:5-6)
The Second Temple was completely destroyed by the Romans in 70AD, as Jesus prophesied in Luke 21. The Western Wall (Wailing Wall) in the Old City of Jerusalem now was originally erected as part of the expansion of the Second Jewish Temple begun by Herod the Great, which resulted in the encasement of the natural, steep hill known as the Temple Mount, in a large rectangular structure topped by a huge flat platform, thus creating more space for the Temple itself and its auxiliary buildings.
The Western Wall is considered holy due to its connection to the Temple Mount. Because of the Temple Mount entry restrictions, the Wall is the holiest place where Jews are permitted to pray. From the early 18th century, it has become a custom that people place slips of paper containing written prayers to God into the cracks of the Western Wall. Over a million notes are placed each year. The notes are collected twice a year and buried on the nearby Mount of Olives.