On April 15, 2013, the 117th Boston Marathon came under attack from two explosives set off near the finish line of the race. Following are some of the early photos to emerge from this horrific event.
Two explosions went off near the finish line of the Boston Marathon -- this was the scene shortly after the first explosion.
Police officers with their guns drawn hear the second explosion.
Copley Square crowds see smoke up ahead.
Ambulances rush to the scene of the bombings.
A member of the bomb squad investigates a suspicious item on the road near Kenmore Square.
Bomb squad members continue investigating the area.
President Barack Obama talks on the phone with FBI Director Robert Mueller to receive an update on the explosions that occurred in Boston, in the Oval Office, April 15, 2013. Seated with the President are Lisa Monaco, Assistant to the President for Homeland Security and Counterterrorism, and Chief of Staff Denis McDonough.
Katherine Swierk, left, is reunited with her aunt Terry Days, center, and friend Jocelyn Cacio outside Copley Square after the explosions.
People on Boylston Street check their mobile devices for news of the explosions. News spread fast over social media networks, particularly Twitter, focusing the international community on the Boston attack.
EMTs transport patients to ambulances from a medical tent in Copley Square.
A marathon runner walks away from the finishing line at the Boston Marathon after the attack.
The FBI arrive at the scene at Dartmouth and Stuart Streets after two explosions rocked the Boston Marathon.
Boston SWAT teams rush to the scene of the explosions that rocked the marathon finishing line.
Boston Police look at blown out windows at the scene of the first explosion on Boylston Street near the finish line of the Boston Marathon.
U.S. Secret Service and U.S. Park Police officers stand guard on Pennsylvania Avenue in front of the White House in the wake of the Boston bombings.
President Barack Obama makes a statement in the White House briefing room about the bombings.
Beacon Street near Kenmore Square remains empty for the use of emergency vehicles in the bombing aftermath.
Fans take a moment of silence in honor of the Boston Marathon explosions before the NHL game between the Phoenix Coyotes and the San Jose Sharks at Jobing.com Arena. Security was tightened throughout the U.S. at major airports and large sporting events in the wake of the Boston attack.
A piece of debris rests against a police barricade near the scene of a twin bombing at the Boston Marathon, on April 16, 2013.