The summer time in the Jewish calendar is a period of progressively intensifying mourning, reaching its peak at the 9th of Av (Tisha beAv). The 9th of Av has a strange double identity: one the one hand it is considered a holiday, yet on the other it is a day of intense mourning. Why do we need to set a time for national mourning? Why relate to the human experience of loss on a specific day?