What is Tisha B’Av? This is a time to mourn for the Jewish people. It takes place on the ninth day of the Jewish month of Av. It is the darkest day on the Jewish calendar — a day of mourning to commemorate the many tragedies that have befallen the Jewish people, many of which have occurred on this day throughout history.
Jews around the world observe this most solemn time in the Jewish year, which marks the destruction of the two Temples in Jerusalem and the exile of the Jewish people from their homeland.
The main events remembered are the destruction of the First and Second Temples in Jerusalem, both of which were destroyed on the ninth of Av, the first by the Babylonians in 586 BCE, and the second by the Romans in 70 CE.