article_snippet.sent: (CNN)When Al-Shabaab gunmen slaughtered 147 people at a college campus in Garissa, Kenya, on Thursday, it was the bloodiest blow Islamist extremists have dealt to the Country since the 1998 bombing of the U.S. Embassy.
article_snippet.sent: But it was also yet another pave stone in the long path of violence between Kenya and the Somali militants.
article_snippet.sent: To understand Thursday's attack, one must understand this: Kenya and Al-Shabaab Al-Shabaab are at war.
article_snippet.sent: Although Al Qaeda's was behind the 1998 attack that killed more than 200 people, Al-Shabaab has killed many more Kenyans and is by far the Country's most persistent tormenter, according to a University of Maryland study.
article_snippet.sent: Thus began a bloody vicious cycle, with Al-Shabaab retaliating on Kenyan soil with ever more spectacular mass killings.
article_snippet.sent: Here are some of the most heinous attacks on Kenya by the Somali terrorist group.
article_snippet.sent: Before the Garissa massacre, the attack was the deepest wound Al-Shabaab had inflicted on Kenya.
highlights_snippet.sent: To understand Thursday's attack, one must understand that Kenya and Al-Shabaab are at war .
  
highlights_snippet.sent: Thursday's attack is the single largest, but Al-Shabaab have killed many more Kenyans .