A man holds a paper reading “I am Charlie” to pay tribute to the people killed at Paris offices of weekly newspaper Charlie Hebdo, in front of the Brandenburg Gate outside the French Embassy in Berlin on Jan. 8, 2015. Masked gunmen stormed the Paris offices of a weekly newspaper that caricatured the Prophet Muhammad, methodically killing 12 people at the offices of the Charlie Hebdo on Jan. 7.Markus Schreiber/The Associated Press
Jan. 7, 2015: A gun assault on the Paris offices of satirical magazine Charlie Hebdo kills 12 people. Al-Qaeda in the Arabian Peninsula claimed responsibility for the attack, saying it was revenge for Charlie Hebdo's depictions of the Prophet Mohammed.
May 24, 2014: Four people are killed at the Jewish Museum in Brussels by an intruder with a Kalashnikov. The accused is a former French fighter linked to the Islamic State group in Syria.
May 22, 2013: Two al-Qaeda inspired extremists run down British soldier Lee Rigby in a London street, then stab and hack him to death.
March, 2012: A gunman claiming links to al-Qaeda kills three Jewish schoolchildren, a rabbi and three paratroopers in Toulouse, France.
July 22, 2011: Anti-Muslim extremist Anders Behring Breivik plants a bomb in Oslo then attacks a youth camp on Norway's Utoya island, killing 77 people, many of them teenagers.
Nov. 2, 2011: Offices of Charlie Hebdo in Paris are firebombed after the satirical magazine runs a cover featuring a caricature of the Prophet Muhammad. No one is injured.
July 7, 2005: Fifty-two commuters are killed when four al-Qaeda-inspired suicide bombers blow themselves up on three London subway trains and a bus.
March 11, 2004: Bombs on rush-hour trains kill 191 people at Madrid's Atocha station in Europe's worst Islamic terror attack.
Aug. 15, 1998: A car bomb planted by an Irish Republican Army splinter group kills 29 people in the town of Omagh, the deadliest single bombing of Northern Ireland's four-decade conflict.
July 25, 1995: A bomb at the Saint-Michel subway station in Paris kills eight people and injures about 150. It was one of a series of bombings claimed by Algeria's GIA, or Armed Islamic Group.