On March 11, Spain marks 20 years since Europe's worst Islamist attack when militants claiming to be acting on behalf of Al-Qaeda bombed commuter trains in Madrid, killing 192 people and wounding nearly 2,000 others. The perpetrators said the attack was revenge for Spain's role in the U.S.-led invasion of Iraq.
A decade later, jihadists invoked the West's intervention against the Islamic State (IS) group in Iraq and Syria to unleash a new wave of terror in Europe. A look back at the deadliest attacks over the past two decades:
2005 London bombings
A year after Spain, London's transport system was targeted on July 7 when four suicide bombers blow themselves up in coordinated strikes on the underground network and a bus. Claimed by Al-Qaeda, the attacks killed 52 people and injure another 700.
2015: Bataclan, Paris
A decade later in France, a new wave of jihadist attacks began, most of which were claimed by the IS. The deadliest took place in Paris on November 13 when IS gunmen went on a shooting and bombing rampage, killing 130 people at the Bataclan concert hall, in bars and restaurants, and at the Stade de France stadium in France's worst post-war attacks.
2016: Brussels airport and metro
On March 22, IS suicide bombers killed 35 people and injured another 340 at Brussels airport and the Maelbeek metro station, near the European Union headquarters.
Belgian investigators said the assailants were part of the same Brussels-based cell that orchestrated the Paris attacks.
2016: Nice attacks
France was again targeted on July 14, Bastille Day, when a radicalised Tunisian drove a truck through the crowds after a fireworks display in the southern resort of Nice, killing 86 people and injuring more than 400.
The attacker was shot dead by police with IS claiming responsibility for the attack. French investigators did not find any links between the assailant and IS.
2017: Manchester pop concert
Back in Britain, a young Briton of Libyan origin blowed himself up at an Ariana Grande pop concert in the city of Manchester on May 22. The attack killed 22 people including seven children and left around 100 injured.
The bombing was claimed by IS, with the 22-year-old assailant using a homemade shrapnel bomb. His family had fought in Libya's civil wars.
2017: Barcelona's Ramblas
On August 17, a group of young radicalised Moroccans and Spaniards of Moroccan origin ploughed a van into pedestrians in Barcelona's famous Ramblas boulevard.
Later, in the early hours of August 18, five others drove a car into pedestrians in Cambrils, a seaside town 100 km (60 miles) further south.
The two attacks, which left 16 people dead and 140 wounded, were claimed by IS and carried out by a cell comprising mostly youngsters who grew up in Catalonia.
