Interfaith Days: Tenth of Tevet

http://www.orazion.org/2014/12/30/
fast-of-10th-of-tevet/

In Judaism, today is the Tenth of Tevet, a fast day. It commemorates the 6th century BCE events at the end of 2 Kings, when Nebachadnezzar II of Babylon besieged Jerusalem and ultimately destroyed the First Temple and conquered Judah. As this site indicates, "More recently, 10 Tevet was chosen to also serve as a “general kaddish day” for the victims of the Holocaust, many of whose day of martyrdom is unknown."