It is the day that Jews remember and cry about the destruction of both temples in Jerusalem--on the exact same day in history almost 700 years apart--in 586 BCE and and 70 AD.
Tisha B'Av is also the date when Germany entered World War I which as we know started a series of events that led to the catastrophe of the Holocaust.
We remember and cry on Tisha B'Av as we went from freedom to worship and live in Jerusalem to the exile and servitude to the Babylonians and the Romans.
It the polar opposite of the holiday of Passover, where we celebrate and commemorate going from servitude under the Egyptians to freedom and redemption to get the Torah and enter and settle the Holy Land.
By the rivers of Babylon
There we sat (and) also wept
When we remembered Zion
On willows in its midst
We hanged up our harps
For there our captors asked of us
(For) words of songs and tormented us (with) mirth:
'Sing to us from the song of Zion'
How will we sing the song of God
On a foreign land?
If I will forget you JerusalemWe as a people have been through so much...servitude, expulsions, crusades, inquisitions, pogroms, genocide...thousands of years of discrimination, torture, rape, and murder--yet, Israel Doth Live!
My right hand will forget (its skill)
My tongue will stick to the roof of my mouth
If I will not remember you
If I will not raise Jerusalem
Above my happiness
As the L-rd promised the Jews--after exile would come redemption, and so it is!
For thousands of years, the Jewish people yearned for a homeland where we could live in peace and security and for the rebuilding of the Holy temple--please G-d in our days soon.
From the rivers of Babylon to the Nile in Egypt and the Rhine in Germany--we have paid the ultimate price and sacrifice to G-d and we pray that the Jewish people can once again be free to live and worship as foretold "from the River in Egypt to the Euphrates River." (Exodus 23:31) ;-)
(Source Photo: Andy Blumenthal)