The Jews believe this day was set aside by God for suffering as per this site. Here are a list of events that happened on that day. Quite shocking actually
- The spies come back with the Nephilim report and the Jews panic, they cry out to God to go back to Egypt
- Both the first and the second temples were destroyed on the same day !
- The Bar Kochba revolt was brutally crushed and many Jews were butchered
- The Temple Mount was plowed over
- They were expelled from England in 1290 AD
- The Golden age of Spain came to an end and Jews were expelled by Ferdinand and Isabella on this date when the Edict of Expulsion came to force
- Germany declared war on Russia and that started the World War on the 9th of Av
Combine this with the fact that to a Jewish mind, prophesy is pattern and co incidence is not a kosher word and you have a grim picture for the month of Av.