"Moses went up to the mountain, and the cloud covered the mountain...for six days. On the seventh day G-d called to Moses from within the cloud... And Moses came within the cloud, and he went up to the top of the mountain, and Moses was upon the mountain forty days and forty nights" (Exodus 24:15-18).
On the morrow of the giving of the Ten Commandments (see Jewish History for the 6th of Sivan), Moses ascended Mount Sinai in order to receive from G-d the remainder of the Torah -- the remaining commandments and the Oral Law. After being "cleansed" by the cloud for six days, he was ushered into the presence of G-d on the 13th of Sivan.
Following the War of Independence (see Jewish History for the 6th of Iyar), citizens in many Arab countries began harassing their Jewish co-citizens, often times inflicting casualties and substantial property damage.
The 5,000 Jews living in Cairo, Egypt were also repeatedly victimized. On the 13th of Sivan a bomb exploded in the Jewish quarter of Cairo, murdering 22 Jews and wounding more than 40 others.
The systematic persecution caused most Egyptian Jews to flee, many choosing to move to Israel. Today, there are virtually no Jews remaining in Egypt.
What does fasting on Yom Kippur achieve?
That even our physical bodies can feel the precious closeness of this day.
Yom Kippur is such a holy day, the body receives life from fasting.