Joshua Nowlan speaks to the media outside the Arapahoe County District courthouse after Phase 2 of Aurora Theater Shooting death penalty hearing for James Holmes. The trial will now proceed to phase 3 to determine if Holmes will be...

Gun Control Advocates Protest at The Nation's Gun Show at the Dulles Expo Center on December 28, 2012 in Dulles, Virginia (Footage by Getty Images)

Montage, siege at Branch Davidian cult compound, ATF agent on roof firing his gun and being shot, wounded being carried away, compound burning. Montage, siege at Branch Davidian cult compound on April 19, 1993 in Waco, Texas (Footage by...

/ David Koresh speaking to disciples in classroom (brief audio). David Koresh in classroom on April 19, 1993 in Waco, Texas (Footage by Getty Images)

Former Democratic Forces for the Liberation of Rwanda (FDLR) combatants and local people attend an Ibiganiro byo Kwibuka, or 'Meeting of Remembering,' at the Mutobo Demobilization Centre April 10, 2014 in Mutobo, Rwanda. The meetings,...

Halloween , Massacre, Genocide - Loopable

Closing remarks with Asa Hutchison: National Rifle Association Executive Vice President Wayne La Pierre press conference following the tragic school shootings at Sandy Hook Elementary in Newtown Connecticut. Famous quote: “The only...

Visitors look at family photos of victims of the 1994 Rwanda genocide hanging inside the Kigali Genocide Memorial Centre April 5, 2014 in Kigali, Rwanda. Rwanda is preparing to commemorate the 20th anniversary of the country's 1994...

Eliot Roger shoots and kills one Univ. of California student outside a deli in Santa Barbara, shoots at others

MS Berlin holocaust memorial / Berlin, Germany

WS Berlin holocaust memorial / Berlin, Germany

National Rifle Association Executive Vice President Wayne La Pierre press conference following the tragic school shootings at Sandy Hook Elementary in Newtown Connecticut. Famous quote: “The only thing that stops a bad guy with a gun...

Halloween , Massacre, Genocide - Loopable

PAN TU Mass graves at Choeung Ek, a Killing Fields memorial / Phnom Penh, Cambodia

Former Serb concentration camp at old mine in Omarska / Skeleton remains from mass graves from Bosnian War / human teeth, bones and clothes laid out on warehouse floor / unidentified and unmatched skeletal remains organised into piles...

A survivor of the Concentration Camp Auschwitz shows her prisoner tattoo. Auschwitz was part of a Nazi program of extermination during World War II.

the memorials pile up as people bring flowers and teddy bears Remembering the Victims at Sandy Hook Elementary on December 15, 2012 in Newtown, Connecticut (Footage by Getty Images)

/ aftermath of FBI siege on the Branch Davidian cult compound / FBI and police walking through building ruins. Aftermath of Waco Siege on April 19, 1993 in Waco, Texas (Footage by Getty Images)

/ ATF FBI agents climbing ladders outside Mount Carmel Center with Branch Davidians inside / ATF agents firing handguns into building / ATF agent on roof of building, peering into window and being hit with bullets. ATF FBI Agents at Waco...

Five survivors of the Waco siege and fire are led into court and are asked questions by reporters. Survivors of Waco siege led into court on April 21, 1993 in Waco, Texas (Footage by Getty Images)

FBI agent Jeff Jamar speaks at press conference about Waco siege and the deaths of the children at the compound. Jeff Jamar speaks to press about Branch Davidian compound siege on April 21, 1993 in Waco, Texas (Footage by Getty Images)

CU Genocide victims’ blood-stained clothing, possessions and bones are on display inside the Nyamata Catholic Church memorial ahead of the 20th anniversary of the country's genocide April 4, 2014 in Nyamata, Rwanda. Attackers used guns...

Showing signs of extreme trauma, victims' skeletal remains, blood-stained clothing and possessions are displayed on metal racks and hanging from the rafters inside the Ntarama Catholic Church genocide memorial ahead of the 20th...

MS Genocide victims’ blood-stained clothing, possessions and bones are on display inside the Nyamata Catholic Church memorial ahead of the 20th anniversary of the country's genocide April 4, 2014 in Nyamata, Rwanda. Attackers used guns...