Tisha B’Av, the 9th day of the month of Av (August 2-3, 2025), is the saddest day on the Jewish calendar, on which we fast, deprive ourselves and pray.

Mourning the destruction of the Temple and the exile of Israel, (see "Today in Jewish History")
we abstain from eating and drinking,bathing, the wearing of leather footwear, and marital relations--for the night and day of Av 9 (i.e., from sundown on Av 8 to nightfall on Av 9). It is customary to sit on the floor or a low seat until after mid-day. Torah study is restricted to laws of mourning, passages describing the destruction of the Temple, and the like. The tefillin are worn only during the afternoon Minchah prayers. (For more laws and customs see this link)
 

May we merit the coming of Moshiach and the rebuilding the Beit Hamikdash when Tisha BAv will be turned into a great Holiday