A man with blood on his shirt is evacuated from Brussels Airport in Zaventem, Belgium, on Tuesday, March 22, 2016. (Photo by Dirk Waem/Belga/Zuma Press/TNS)

An artistic light installation illuminates the canal near the Brussels district of Molenbeek during the Bright Brussels Festival in Brussels, Belgium February 4, 2017. (Photo by Francois Lenoir/Reuters)

A 3D printing professional wears his T-Rex skull creation during a 3D printing show in Brussels, Belgium, October 18, 2015. (Photo by Eric Vidal/Reuters)

People take part in The Color Run in Brussels, Belgium September 6, 2015. The Color Run is a five-kilometre, untimed race, held in cities worldwide, with the aim of promoting healthy living. Participants are doused from head to toe in different colors at each kilometre. (Photo by Yves Herman/Reuters)

Chocolate-lovers have gathered for the first Salon du Chocolat fashion show and festival in Brussels. The festival takes place in 19 cities worldwide, but this year marks the first Salon du Chocolat in Brussels. The main feature of the festival was a fashion show, where chefs and designers collaborated to create chocolate outfits. (Photo by Farrukh Younus/Implausibleblog)

People walk with their arms raised as security forces restore order in Nice, France on July 14, 2016. (Photo by SIPA Press/Rex Features/Shutterstock)

Police officers escort people from inside the shopping center as they respond to a shooting at the Olympia Einkaufzentrum (OEZ) at July 22, 2016 in Munich, Germany. According to reports, several people have been killed and an unknown number injured in a shooting at a shopping centre in the north-western Moosach district in Munich. Police are hunting the attacker or attackers who are thought to be still at large. (Photo by Joerg Koch/Getty Images)

An Afghan policeman stands guard as smoke and flames rise from the site of a huge blast struck near the entrance of Kabul's international airport, in Kabul on August 10, 2015. A huge blast struck near the entrance of Kabul's international airport on August 10 during the peak lunchtime period, officials said, warning that heavy casualties were expected. “The explosion occurred at the first check point of Kabul airport”, said deputy Kabul police chief Sayed Gul Agha Rouhani. (Photo by Shah Marai/AFP Photo)