After a flurry of confusion and chaos, we are starting to get a clearer picture of just what happened at the Boston Marathon bombings. The Boston Globe released an updated map and timeline that pieces the scene together.
The final leg of the marathon was on Boylston Street, and the runners were approaching the finish line from the west side:
The first bomb went off at approximately 2:50 p.m. ET, several hundred feet ahead of the finish line. As you can see in the picture below, the medical tent was located around the block.
The second bomb was detonated 13 seconds later, and happened about 500 feet west of the first bomb, near the corner of Boylston Street and Ring Road.
Authorities discovered a third bomb on the other side of the finish line, close to Dartmouth Street. It was detonated in a controlled environment without incident.
You can see the complete map and timeline at the Globe's official website.