The attack on Tunisia's famed Bardo Museum is just the latest evidence that parts of North and sub-Saharan Africa have become a magnet for Islamist extremism.
Tunisia -- lying just across the Mediterranean from Europe, but bordered on one side by Libya and on the other by Algeria -- has until now not suffered the kind of large-scale terror attacks seen in both those nations in recent years.
But it has emerged as a place of increasing concern as the threat of Islamist extremism has intensified in the region.
Islamist terrorists also have struck in Algeria, where they killed at least 37 hostages at a gas field in 2013, and in Libya, where terrorists killed the U.S. ambassador and three others in 2012 and where ISIS has established a beachhead in the east.
Al Qaeda's North African offshoot Al Qaeda in the Islamic Maghreb (AQIM), which has its roots in Algeria, has captured territory in Mali and taken hostages -- often Europeans -- in countries such as Niger and Mauritania.
So what is the world doing about it? The United States has created a military command in Africa and also established a special operations base in Djibouti, which borders Somalia in the Horn of Africa. France has sent troops to Mali. And, as CNN recently reported from Chad, Western militaries have trained special forces from several northern African nations to take on the Islamists.