tripoli don't govern their territory, and there are roving isis cells that are expanding. so a lot of these tunisian fighters that have gone to syria and iraq have gone there through training camps in libya. some of them are coming back to tunisia and some will be coming home from syria and iraq. this will be a huge challenge for tunisia. >> reporter: the museum attack is just one example of how difficult safeguarding tunisia will be as militant groups like isis are intent on destroying its young democracy. atika scubert, cnn, london. terror groups like isis and al qaeda make no secret about their desire to strike the west. and it becomes even easier when international tourists visit places like tunisia and egypt. as miguel marquez reports, it's not the first time terrorists have targeted tourists with deadly results. >> reporter: the targeting of tunisia's most prominent museum.