Five misfortunes befell our fathers … on the ninth of Av. …On the ninth of Av it was decreed that our fathers should not enter the [Promised] Land, the Temple was destroyed the first and second time, Bethar was captured and the city [Jerusalem] was ploughed up. — Mishnah Ta’anit 4:6
Today is Tisha B’Av, the Fast of the Ninth of Av, a day of mourning to commemorate the destruction of the first and second Temples, both of which were destroyed on the ninth of Av. The first Temple was destroyed by the Babylonians in 586 B.C.E.; the second by the Romans in 70 C.E.
The story is told of Napoleon, who, walking through the streets of Paris, passed by a synagogue. He heard the sound of people praying and weeping inside. Turning to one of his aides, a Jewish officer, the emperor asked, “What is going on in there?”