Fireworks explode over the St. Sava monument during the Orthodox Christian New Year's Day celebrations in Belgrade, Serbia, January 14, 2018. REUTERS/Djordje Kojadinovic

Fireworks explode over the St. Sava monument during the Orthodox Christian New Year's Day celebrations in Belgrade, Serbia, January 14, 2018. REUTERS/Djordje Kojadinovic

Fireworks explode over the St. Sava temple during the Orthodox Christian New Year's Day celebrations in Belgrade, Serbia, January 14, 2018. REUTERS/Djordje Kojadinovic

An illustration picture shows roasted coffee beans in Brussels, Belgium May 1, 2017. REUTERS/Eric Vidal/Illustration

An illustration picture shows roasted coffee beans in Brussels, Belgium May 1, 2017. REUTERS/Eric Vidal/Illustration

An illustration picture shows a coffee cup and roasted coffee beans in Brussels, Belgium May 1, 2017. REUTERS/Eric Vidal/Illustration

An illustration picture shows roasted coffee beans in Brussels, Belgium May 1, 2017. REUTERS/Eric Vidal/Illustration

An illustration picture shows bubbles in a coffee cup in Brussels, Belgium May 1, 2017. REUTERS/Eric Vidal/Illustration

An illustration picture shows coffee heating in an Italian coffee maker in Brussels, Belgium May 1, 2017. REUTERS/Eric Vidal/Illustration

An illustration picture shows a coffee cup near a laptop in Brussels, Belgium May 1, 2017. REUTERS/Eric Vidal/Illustration

Guests show their excitement as they wait in viewing pens to see Pope Francis emerge from a private meeting with U.S. President Barack Obama upon the Pope's arrival at Joint Base Andrews outside Washington September 22, 2015.REUTERS/Jonathan Ernst

Thrill-seekers ride a fairground attraction near the London Eye ferris wheel in London, Britain August 29, 2015. REUTERS/Neil Hall

Thrill-seekers ride a fairground attraction near the London Eye ferris wheel in London, Britain August 29, 2015. REUTERS/Neil Hall TPX IMAGES OF THE DAY

Graduates toss their caps in the air at the conclusion of the commencement ceremony for the U.S. Naval Academy Class of 2015 in Annapolis, Maryland May 22, 2015. REUTERS/Kevin Lamarque TPX IMAGES OF THE DAY

Pope Francis arrives to attend a special audience with nuns of the Rome's diocese in Paul VI hall at the Vatican, May 16, 2015. REUTERS/Tony Gentile TPX IMAGES OF THE DAY

Children participate in a protest against police brutality against minorities, in New York April 14, 2015. Protestors angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Brendan McDermid

Children participate in a protest against police brutality against minorities, in New York April 14, 2015. Protestors angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Brendan McDermid

Demonstrators climb on the Brooklyn Bridge during a protest against police brutality against minorities, in New York April 14, 2015. Protestors angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Brendan McDermid

Demonstrators stop traffic on the Brooklyn Bridge during a protest against police brutality against minorities, in New York April 14, 2015. Protestors angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Brendan McDermid

A demonstrator sits on the roadway during a protest against police brutality against minorities, in New York April 14, 2015. Protesters angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Brendan McDermid

Demonstrators protest against police brutality against minorities, in New York April 14, 2015. Protestors angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Brendan McDermid

A news photographer is knocked down by a NYPD officer (unseen) as another police officer approaches him during a protest against police brutality against minorities, in New York April 14, 2015. Protesters angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Brendan McDermid

A demonstrator is detained by NYPD officers on the Brooklyn Bridge roadway during a protest against police brutality against minorities, in New York April 14, 2015. Protestors angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Brendan McDermid

Demonstrators stop traffic on the Brooklyn Bridge during a protest against police brutality against minorities, in New York April 14, 2015. Protestors angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Brendan McDermid

A demonstrator sits on a road during a protest against police brutality against minorities, in New York April 14, 2015. Protestors angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. The poster refers to Mumia Abu-Jamal, a former black nationalist and public radio reporter who is serving life in prison for the 1981 murder of a Philadelphia police officer. REUTERS/Brendan McDermid

Demonstrators stop traffic on the Brooklyn Bridge during a protest against police brutality against minorities, in New York April 14, 2015. Protestors angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Brendan McDermid

Demonstrators stop traffic on the Brooklyn Bridge during a protest against police brutality against minorities, in New York April 14, 2015. Protestors angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Brendan McDermid

A demonstrator is detained by NYPD officers on the Brooklyn Bridge roadway during a protest against police brutality against minorities, in New York April 14, 2015. Protestors angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Brendan McDermid

A demonstrator is detained by NYPD officers on the Brooklyn Bridge roadway during a protest against police brutality against minorities, in New York April 14, 2015. Protestors angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Brendan McDermid

A demonstrator is detained by NYPD officers on the Brooklyn Bridge roadway during a protest against police brutality against minorities, in New York April 14, 2015. Protesters angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Brendan McDermid

Demonstrators stop traffic on the Brooklyn Bridge during a protest against police brutality against minorities, in New York April 14, 2015. Protestors angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Brendan McDermid

Demonstrators stop traffic on the Brooklyn Bridge during a protest against police brutality against minorities, in New York April 14, 2015. Protesters angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Brendan McDermid

Demonstrators stop traffic on the Brooklyn Bridge during a protest against police brutality against minorities, in New York April 14, 2015. Protesters angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Brendan McDermid

Demonstrators are detained by NYPD officers on the Brooklyn Bridge roadway during a protest against police brutality against minorities, in New York April 14, 2015. Protesters angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Brendan McDermid

Demonstrators are escorted off the Brooklyn Bridge roadway by NYPD officers during a protest against police brutality against minorities, in New York April 14, 2015. Protesters angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network," hoping to invigorate a national discussion on the thorny issue. REUTERS/Brendan McDermid

Demonstrators are escorted off the Brooklyn Bridge roadway by NYPD officers during a protest against police brutality against minorities, in New York April 14, 2015. Protesters angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network," hoping to invigorate a national discussion on the thorny issue. REUTERS/Brendan McDermid

Demonstrators are escorted by the NYPD off the Brooklyn Bridge roadway during a protest against police brutality against minorities in New York, April 14, 2015. Protestors angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Shannon Stapleton

Demonstrators are escorted by the NYPD off the Brooklyn Bridge roadway during a protest against police brutality against minorities in New York, April 14, 2015. Protestors angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Shannon Stapleton

Demonstrators are escorted by the NYPD off the Brooklyn Bridge roadway during a protest against police brutality against minorities in New York, April 14, 2015. Protestors angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Shannon Stapleton

Demonstrators are escorted by the NYPD off the Brooklyn Bridge roadway during a protest against police brutality against minorities in New York, April 14, 2015. Protestors angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Shannon Stapleton

People hold their hands up inside a vehicle as they are stopped by the NYPD on the Brooklyn Bridge roadway during a protest against police brutality against minorities in New York, April 14, 2015. Protestors angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Shannon Stapleton

A person holds up hands inside a vehicle as they are stopped by the NYPD on the Brooklyn Bridge roadway during a protest against police brutality against minorities in New York, April 14, 2015. Protestors angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Shannon Stapleton

Demonstrators run over the Brooklyn Bridge roadway during a protest against police brutality against minorities in New York, April 14, 2015. Protestors angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Shannon Stapleton

Demonstrators embrace during a protest against police brutality against minorities at Union Square in New York, April 14, 2015. Protestors angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Shannon Stapleton

Demonstrators march past a taxi during a protest against police brutality against minorities in New York, April 14, 2015. Protestors angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Shannon Stapleton

Demonstrators climb over a fence during a protest against police brutality against minorities in New York, April 14, 2015. Protestors angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Shannon Stapleton

Demonstrators climb over a fence during a protest against police brutality against minorities in New York, April 14, 2015. Protestors angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Shannon Stapleton

Demonstrators climb over a fence during a protest against police brutality against minorities in New York, April 14, 2015. Protestors angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Shannon Stapleton

Activist Cornel West marches with demonstrators during a protest against police brutality against minorities in New York, April 14, 2015. Protestors angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Shannon Stapleton

Demonstrators protest against police brutality against minorities during a protest in New York, April 14, 2015. Protestors angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Shannon Stapleton

Demonstrators protest against police brutality against minorities during a protest in New York, April 14, 2015. Protestors angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Shannon Stapleton

Demonstrators protest against police brutality against minorities during a protest in New York, April 14, 2015. Protestors angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Shannon Stapleton

Demonstrators protest against police brutality against minorities during a protest in New York, April 14, 2015. Protestors angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Shannon Stapleton

Demonstrators protest against police brutality against minorities during a protest in New York, April 14, 2015. Protestors angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Shannon Stapleton

Demonstrators protest against police brutality against minorities during a protest in New York, April 14, 2015. Protestors angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Shannon Stapleton

Demonstrators protest against police brutality against minorities during a protest in New York, April 14, 2015. Protestors angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Shannon Stapleton

Demonstrators protest against police brutality against minorities during a protest in New York, April 14, 2015. Protestors angered by fresh cases of police violence against unarmed black men in the United States gathered on Tuesday in New York City in a protest organized by the group "Stop Mass Incarceration Network" hoping to invigorate a national discussion on the thorny issue. REUTERS/Shannon Stapleton TPX IMAGES OF THE DAY

Afghan children enjoy a ride in Kabul March 30, 2015. REUTERS/Mohammad Ismail TPX IMAGES OF THE DAY

People visit a park with blooming flowers during spring in Shanghai March 24, 2015. REUTERS/Aly Song TPX IMAGES OF THE DAY