Shabbat, July 10, 2021 is the first day of the month Av.
The first nine days of Av are days of mourning for the destruction of the first and second Holy Temples. Among other observances, during this time we refrain from eating meat or drinking wine (except on Shabbat), swimming or bathing for pleasure, remodeling or expanding a home and buying new clothes.
The Nine Days culminate in the fast of Tisha B'Av (The Ninth of Av) on Sunday, July 18, 2021.