D.C. ranks fifth in the nation as a terrorist "hot spot," according to a new study.
The University of Maryland released a map identifying terrorism "hot spots" across the nation. The District earned fifth place for having been targeted 79 times in the past four decades.
The study was funded by the Department of Homeland Security.
"Every single state has at least one attack in it and in some cases there's even quite a lot of activity even in rural areas," said Gary LaFree, of the National Consortium for the Study of Terrorism.
The Consortium found that from 1970 to 2008 nearly one-third of all terrorist attacks happened in five metropolitan areas: New York, Los Angeles, Miami, San Francisco and Washington, D.C.
"We used the American military definition of terrorism which is an attack where there is violence or a threat of violence carried out by someone other than a government," LaFree said.
While the work terrorism may evoke images of 9/11, experts say terror has come in many forms and many actors, including extreme right-wing and left-wing groups.
Groups motivated by religious beliefs, international politics and environmental concerns, like the Discovery Channel attack.
The researchers even consider the Columbine Massacre a terrorist attack because of the shooters' journal entries plotting world domination. Virginia Tech was not included because of Seung-Hui Cho's mental health issues.
"A homicide wouldn't be considered unless it was an assassination for a political reason or related to a political hate crime," LaFree said.
Using all the data, researchers say they've found waves in violence over time and other patterns that could help law enforcement prevent future attacks.
"International groups tend to take a long time to plan attacks, sometimes several years. On the other hand, environmental groups have a short window between when the plot is hatched and when they carry it out," he said.
The researchers say they've already heard from congressional staffers and intelligence officials with questions about the study. It could prove to be critical tracking terrorists and deciding how to distribute homeland security resources.