The day after the November 2015 Paris attacks, which left over 130 people dead, the city was in mourning. When German pianist Davide Martello began playing John Lennon's "Imagine" outside the Bataclan on a piano he had transported from Germany, a crowd quickly gathered. Martello later told The Guardian that "I wanted to be there to try and comfort, and offer a sign of hope."

After the chaos of a tragedy, a simple visual image can be a comfort. French graphic artist Jean Jullien posted a hand-painted peace sign incorporating an image of the Eiffel Tower on social media after the November 2015 attack in Paris. It quickly became an iconic symbol of sympathy with survivors.

Artists do not always play a peaceful role. The comic artist known as Charb was famous for publishing offensive caricatures of religions, including Islam. After Islamist gunmen shot him and his colleages to death in the offices of Charlie Hebdo on Jan. 7, 2015, demonstrators used his images to defy the attackers and their supporters.

Artists are sometimes the targets of terrorist groups. Such was the fate of Syrian pianist Aeham Ahmad, who studied music in Damascus and Homs but spent much of his life in a refugee settlement. It was on a bombed-out street there that Ahmad gained international attention, playing piano in a YouTube video. After ISIS militants burned his instrument, he fled to Germany and now lives there.

Aristotle's theory of catharsis - purging emotions through theater - lives on. Austrian Elfriede Jelinek crafted her play "Anger" (pictured above in a 2016 production at the Hamburger Thalia-Theater) while in shock from the 2015 attacks in Paris. The title points not only to the anger of the attackers, but also the hatefulness of some responses, as well as the agony of those caught in the middle.

On March 13, 2016, Al-Qaeda militants gunned down 19 people on the Ivory Coast's sandy Grand Bassam beach. Ten days later, a number of the country's pop stars released a music video to reclaim the space. "Meme pas peur" is the name of the song - "Not even scared" - and the defiant words ring true among performers as they dance on the sun-bleached sand, no blood in sight.

Not all artistic responses to violence are literal. The vivid colors and lively shapes of Guillaume Bottazzi's abstract art speak for themselves as a reponse to tragedy. Since the end of October, he has been working on a mural in Brussels's Place Jourdan as a permanent memorial to the victims of the March 22 attacks in the city.

American pop artist Jeff Koons unveiled his plan for "Bouquet of Tulips 2016" at a ceremony in Paris in November. The forthcoming sculpture, by one of the world's wealthiest artists who hires workers to construct his designs, was donated in honor of the victims of the multiple Paris terrorist attacks of 2015.

On December 20, a day after an attack on a Berlin Christmas market claimed 12 lives, the Brandenburg Gate was lit with the colors of the German flag. On Friday, December 23, the city will hold a six-hour long memorial concert featuring several German musicians as a sign of Berlin's resilience to the disruption of an otherwise festive public life in the week before Christmas.