Tisha B'Av is a significant day of mourning in the Jewish calendar, observed on the ninth day of the month of Av. It commemorates the destruction of the First Temple in 586 BCE and the Second Temple in 70 CE, both pivotal events in Jewish history. The day is marked by fasting, prayer, and reflection on the tragedies that have befallen the Jewish people. On Tisha B'Av, many Jews refrain from eating, drinking, and engaging in joyful activities. Special services are held, including the reading of the Book of Lamentations, which expresses sorrow over the destruction of the Temple. The day serves as a reminder of loss and the importance of unity and resilience within the Jewish community.