Jewish

Shavuot is a major Jewish holiday celebrating the giving of the Torah at Mount Sinai and the grain harvest, marked by dairy meals, studying Torah, and hearing the Ten Commandments.

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. It is regarded as the saddest day in the Jewish calendar.