c 1476 BCE- Manna fell in the wilderness for the first time. Moses introduced the first bracha [blessing] of the Birchat HaMazon [grace after meals] when Israel began to receive the manna.
66 CE- The Roman legion under Afolorus ransacked Yerushalayim, killing 3000+ Jews.
70 CE- Titus and the Roman army laid siege to Jerusalem, greatly weakening its defenders. The Romans recaptured the middle wall of Jerusalem and demolished it. The city was later burned, its inhabitants massacred, and the Holy Temple destroyed on the 9th of Av.
May 18, 1881- Anti-Jewish riots in Odessa, Russia.
May 18, 1897- Anti-Jewish riots erupted in Algeria.
May 7, 1909- Construction began on the first 100 houses to be built in Achuzat Bayit (later known as Tel Aviv).
May 5, 1939- The Nazi Nuremberg anti-Jewish Laws, depriving Jews the rights citizenship, were passed by the government of Nazi Germany in 1935. On 16 Iyar 1939, the laws went into effect in Nazi-allied Hungary.
April 29, 1945- The U.S. 7th Army liberated the Dachau concentration camp. Dachau was the first Nazi concentration camp and the model for the other concentration camps. During the war, 200,000 Jews were housed in Dachau. More than 30,000 were killed and tens of thousands died due to the conditions and spread of disease in the camp. The camp was freed by the 45th Infantry Division of the U.S. Seventh Army. It was the second concentration camp to be liberated following the end of WWII. The U.S. troops forced the citizens of the local community to come to the camp, observe the conditions, and help clean the facilities.
May 18, 1965- The Syrians hang Eli Cohen publicly in Damascus as an Israeli spy, refusing even until today to return his remains to his family.