Tisha BeAv (Ninth of Av in Hebrew calendar), is a day of mourning that marks the day of destruction of the first and second Beit HaMikdash (Temple), leading to the expulsion of Jews from Israel.
Bible Reference: Jeremiah Chapter 39
in the ninth year of Zedekiah king of Judah, in the tenth month, came Nebuchadrezzar king of Babylon and all his army against Jerusalem, and besieged it;
in the eleventh year of Zedekiah, in the fourth month, the ninth day of the month, a breach was made in the city
The Second Temple was destroyed by the Romans in 70 CE (see History of Israel).
Ten of the 12 spies that were sent by Moses returned after 40 days of exploring the land of Israel and "spread an evil report of the land..." "and the people wept that night" (Bible reference: Numbers, 13:32; Numbers 14:1
Expulsion of Jews from Spain in 1492.