The Saddest Day in Jewish History

When Moses sent the twelve spies into Canaan, only two, Joshua and Caleb, came back with a positive report.  God declared that that present generation would not enter the Promised Land and that the day, the ninth of Av, would become one of crying for their descendents. (Numbers 13 and 14.)

The destruction of the Temple in Jerusalem in 586 BC/BCE occurred on Tisha b'av, the ninth day of the month of Av (Hebrew Calendar).

The destruction of the Second Jewish Temple by Rome in 70 AD/CE occurred on the ninth of Av.

The Romans put down the Bar Kochba Revolt and destroyed the city of Betar in 132 AD/CE, on the ninth of Av.  Over 100,000 Jews were killed.

In 133 AD/CE, on the ninth of Av, the Roman commander Turnus Rufus plowed the site of the Temple.

The expulsion of the Jews from England in 1290 and from Spain in 1492 by King Ferdinand, the declaration of the First Crusade, the outbreak of World War I, and the deportation of Warsaw's Jews to the Treblinka Death Camp are all sometimes associated with the 9th of Av but did not occur on that day.  The Warsaw deportation is the closest to the correct date, beginning as it did on the 10th of Av.

Tisha B'Av is an annual fast day in Judaism.  Observant Jews do not eat, drink, work, bathe, wear leather shoes, or have sex on this day because it is a day of mourning.