Look back at Boston Marathon bombing

POSTED: 01:24 PM PDT Apr 15, 2013    UPDATED: 07:22 AM PST Jan 05, 2015 
Boston Marathon first explosion goes off

The trial for Dzhokhar Tsarnaev, the man charged in the Boston Marathon bombings that killed three people and injured more than 200, begins Monday. Take a look back at scenes from the April 15, 2013, incident.