Jerusalem's Bloody Tuesday

Two Palestinian cousins wielding axes, knives and guns burst into a synagogue in West Jerusalem and murdered four rabbis, three of whom are American, and injured several more worshipers severely before police shot them to death.  While not expressly claiming credit, Hamas praised the attackers, as Palestinian Authority leader Mamoud Abbas condemned the murders. The Israeli government promised swift and harsh retaliation for the murders, and immediately ordered the destruction of the cousins' homes in the Gaza strip and arrests of family members believed to have had prior knowledge of the attack.

With the peace process all but derailed, this may have been the final blow to any resolution of issues dividing Israelis and Palestinians for the foreseeable future.