On the 10th of Tevet of the year 3336 from Creation (425 BCE), the armies of the Babylonian emperor Nebuchadnezzar laid siege to Jerusalem. Thirty months later -- on Tammuz 17, 3338 -- the city walls were breached, and on 9 Av of that year, the Holy Temple was destroyed. The Jewish people were exiled to Babylonia for 70 years.
Link: Asarah B'Tevet
Tevet 10 is observed as a day of fasting, mourning and repentance, in remembrance of the siege of Jerusalem. We refrain from food and drink from dawn to nightfall, and add the Selichot and other special supplements to our prayers. (More recently, Tevet 10 was chosen to also serve as a "general kaddish day" for the victims of the Holocaust, many of whose day of martyrdom is unknown.)
Links:
Learn about Tevet 10
Essays and Stories on the Holocaust
Look deeply and you will see that the Torah does not know of man and woman as separate beings.
Each act is performed once through a single body—a body that in our world may appear as two, but which the Torah sees as one.
On the contrary, for both to be assigned the same mitzvah would be redundant, for why should one half of the body do that which the other has already accomplished?
Just as a man fulfills the mitzvah to be fruitful and multiply through the agency of his female counterpart, so does a woman wrap tefillin or wear tzitzit on the body of her male counterpart.
For just as man and woman were first created as a single form, so too, before each soul descends below, they begin as one.
It may be at times that only half a soul must descend for its divine mission, while the other half waits patiently above. And when it will return, they will merge once again.