The ninth day of the month of Av is the major day of communal mourning in the Jewish calendar. Although a large number of disasters are said to have befallen the Jews on this day, the major commemoration is of the destruction of the First and Second Temples in Jerusalem in 586 B.C.E. and 70 C.E., respectively. Megillat Eicha (the scroll of Lamentations), which is a lament for the destruction of the First Temple, is chanted during the Maariv service along with several kinot (elegies or dirges) written at different periods of Jewish history.
When Tisha B'Av falls on Shabbat, the observance is delayed to the tenth day of Av.
Saturday, July 21
9:00 p.m. – Erev Service followed by the reading of Eicha
Sunday, July 22
9:00 a.m. – Shacharit and chanting of the Book of Eicha
2:00 p.m. – Mincha