
Airport workers and their relatives in Brussels, Belgium, hold a candlelight vigil Wednesday, March 23, to pay tribute to those who were killed in terrorist attacks the day before. On Tuesday, explosions rocked the city's airport and a subway station.

Belgian national flags are projected onto the National Gallery in London's Trafalgar Square on March 23.

A woman in Brussels pauses after people observed a minute of silence at the Place de la Bourse on March 23.

Teresa Mancheno, a maintenance worker at Newark Liberty International Airport, attends a vigil in Newark, New Jersey, on March 23.

European Union flags fly at half-staff outside the European Commission in Brussels on March 23.

A young girl lights a candle at the Place de la Bourse in Brussels on Tuesday, March 22.

An image of the Belgian flag is displayed on the Trevi Fountain in Rome on March 22.

The Eiffel Tower is lit up with the colors of the Belgian flag on March 22.

Servicemen with Azov, a Ukrainian volunteer battalion, hold torches during a tribute ceremony at the Belgian Embassy in Kiev, Ukraine, on March 22.

U.S. President Barack Obama and his family observe a moment of silence as they attend a baseball game in Havana, Cuba, with Cuban President Raul Castro, right, on March 22.

A woman reads messages written on the ground at Brussels' Place de la Bourse on March 22.

A New York City church holds Mass for victims of the Brussels attacks on March 22.

A man places flowers outside the Belgian Embassy in Moscow on March 22.

A man looks at flowers and messages outside the stock exchange in Brussels on March 22.

Democratic presidential candidate Hillary Clinton, center, stands for a moment of silence during a roundtable with tribal leaders in Puyallup, Washington, on March 22.

A woman leaves a bouquet of flowers at the base of the Belgium and European Union flags, which were flying at half-staff March 22 at the Belgian Embassy in Washington.

Activists in Multan, Pakistan, condemn the Brussels attack on March 22.

A woman lays flowers at the steps of the Belgian Embassy in Berlin on March 22.

A boy at a makeshift migrant camp shows support for the victims near the village of Idomeni, Greece, on March 22.

Mayors of Istanbul districts walk with consuls from various countries, including Belgium, during a protest condemning terrorism on March 22.

People in Turin, Italy, take part in a rally to remember the victims on March 22.

France's Parliament observes a minute of silence on March 22.

Members of Quebec's National Assembly have a moment of silence on March 22.