Shalom.

Tisha B'Av is the saddest day on the Jewish calendar because of the incredible series of tragedies which occurred on that date throughout Jewish History.

Tisha B'Av means "the ninth (day) of the Hebrew month of Av." Tisha B'Av primarily commemorates the destruction of the first and second Temples, both of which were destroyed on the ninth of Av (the first by the Babylonians in 586 B.C.E.; the second by the Romans in 70 C.E.).

Although this day is primarily meant to commemorate the destruction of the Temple, it is appropriate to consider on this day the many other tragedies of the Jewish people, many of which occurred on this day, most notably the expulsion of the Jews from Spain in 1492.

You can learn more about this Jewish fast day (begins Monday evening, August 8, 2011) at:
http://www.jr.co.il/hotsites/j-hdayav.htm

May we see the rebuilding of the Temple in our days and that Tisha B'Av becomes a day of celebration.

If you are fasting: Have a meaningful fast.

Jacob