We track four people on their journey.
Why Iraqi refugees abandon Europe and return home
19 Apr 2013 12:10 GMT
Massachusetts State Police Timothy Alben, left, speaks to reporters on Friday about the status of the two suspects in the Boston Marathon bombings in Watertown, Massachusetts [Reuters]
Police officers search around buildings at the Massachusetts Institute of Technology near where a police officer was shot in Cambridge on Thursday [Reuters]
Police officers secure a school building at the MIT campus near where the police officer was believed to have been shot [Reuters]
Gunshots were heard near a building on the campus of MIT in Cambridge, Massachusetts, the university said on its website on Thursday [Reuters]
Massachusetts state police, Cambridge Police and MIT Police search at the scene of the shooting in Cambridge on Thursday [EPA]
Media reports cited the Massachusetts state police in reporting that an officer had died in the shootout [EPA]
A Massachusetts state police officer stands guard at the scene after explosions hit the 117th Boston Marathon in the US city on April 15 [Reuters]
Transport apps are revolutionising commutes for the middle classes, but poorer citizens still face daily gridlock.
Poverty & Development, Asia, India
Cubans get amnesty at the US border, but reaching it involves a risky journey along the Central American migrant trail.
Human Rights, Latin America, Cuba
In many ways, Michael is just like any other 11-year-old, but he has had four open heart surgeries.
Health, US & Canada
Follow a dancer through the exhaustion and jubilation of Peru's days-long Virgin of Candelaria festival.
Arts & Culture, Latin America, Peru
We travel to Chile to meet a group of young scientists determined to develop smart plant-based food to save the planet.
Science & Technology, Chile, Food
We follow the journey of a plastic bottle to find out what it takes to truly recycle the product creating zero waste.
Science & Technology, US & Canada, Environment
A couple working to protect LA communities from gang violence is caught in the crossfire of the US war on gangs.
Politics, Gang violence, US
South Koreans drink twice as much liquor as Russians, but is this national obsession with alcohol reversible?
Health, Asia, South Korea