1) Recently discovered 11th century moat just outside of the southern Old City walls of Jerusalem between Zion and Dung gates that is part of the Mount Zion Archaeological Project. The moat was built by the Fatimid Egyptian defenders of the city against the attacking Crusaders.

2) After the Crusader forces breached the walls in 1099 they massacred the Muslim and Jewish inhabitants. The Jewish community was locked in the central synagogue and burnt alive. The First Crusade also passed through Germany where they mass murdered Jews in 1096,

3) known as the Rhineland massacres. The Rhineland massacres are possibly why Ashkenazi Jews experienced a genetic bottleneck of just 350 people which is why we are all 30th cousins or less.