Tisha B'Av is an annual fast day in Judaism, on which a number of disasters in Jewish history occurred, primarily the destruction of both Solomon's Temple by the Neo-Babylonian Empire and the Second Temple by the Roman Empire in Jerusalem.
Destruction of the Temple of Jerusalem, by Francesco Hayez
Excavated stones from the Western Wall of the Temple Mount (Jerusalem, Israel), knocked onto the street below by Roman battering rams in 70 CE
Reading kinnot at the Western Wall
Lamenting in the synagogue, 1887
Av is the eleventh month of the civil year and the fifth month of the ecclesiastical year on the Hebrew calendar. It is a month of 30 days, and usually occurs in July–August on the Gregorian calendar.
Francesco Hayez, The Second Temple in flames, 1867. The 9th of Av, Tisha B'Av, is a fast commemorating what has been called the saddest day in Jewish history, which is when the Holy Temple was set aflame.