I added the BHO part. I hope they don't delete it.
Other calamities associated with Tisha B'Av:
The episode of the Golden calf (17th of Tammuz) in which the Hebrews, after their exodus from Egypt, reintroduced idolatry as a form of spirituality.[8][9]
The First Crusade officially commenced on August 15, 1096 (Av 24, AM 4856), killing 10,000 Jews in its first month and destroying Jewish communities in France and the Rhineland. A grand total of 1.2 million Jews were killed by this crusade that started on the 9th of Av.[6][10]
The Jews were expelled from England on July 18, 1290 (Av 9, AM 5050).[6]
The Jews were expelled from France on July 22, 1306 (Av 10, AM 5066).
The Jews were expelled from Spain on July 31, 1492 (Av 7, AM 5252).[7]
Germany entered World War I on August 1–2, 1914 (Av 9-10, AM 5674), which caused massive upheaval in European Jewry and whose aftermath led to the Holocaust.[6]
On August 2, 1941 (Av 9, AM 5701), SS commander Heinrich Himmler formally received approval from the Nazi Party for "The Final Solution". Almost one third of world's Jewish population were captured and killed at that time.
On July 23, 1942 (Av 9, AM 5702), began the mass deportation of Jews from the Warsaw Ghetto, en route to Treblinka.
Most religious communities use Tisha B'Av to mourn the 6,000,000 Jews who perished in the Holocaust, including special kinnot composed for this purpose (see the main kinnot article) (in addition to, or instead of, the secular Holocaust Memorial Days.)
On July 27, 2004 (Av 9, AM 5764), Barack Hussein Obama spoke at the Democrat National Convention. Some Jews see this as a disaster which led to his Presidency, which is widely seen as Anti-Israel by many Jews.
On the 10th of Av the following events took place:
AMIA bombing of the Jewish community center in Buenos Aires, killing 85 and injuring 300 on 18 July 1994; 10 Av, AM 5754.
Israel's unilateral disengagement plan, also known as the "Disengagement plan", "Gaza expulsion plan", or Hitnatkut, began 10 Av, AM 5765; 15 August 2005.