Horrific. I have been at the site of the bombings many times in my life. My daughter went to college near there. I have been a spectator at the Boston Marathon many, many times. I have friends who have run it. Horrific.
The bombings may have been an act of terrorism. Your insurance policies may not consider the events to be terrorism, though.
The Terrorism Risk Insurance Act (TRIA) allowed for specific insurance coverages. It also defined a certified act of terrorism as an event where there are more than $5,000,000 in losses concurrent with a declaration by the Secretary of the Treasury, the Secretary of State, and the US Attorney General.
Most commercial insurance policies now include an offer of insurance for certified acts of terrorism at an additional premium. Without buying the coverage, most policies will exclude certified acts. Some insurance policies have broader exclusions – meaning terrorist acts not certified may be excluded.