An Army Black Hawk helicopter collided with an American Airlines plane in Washington D.C. near the Reagan National Airport, killing 67 people on Tuesday night. The plane crash happened in one of the U.S.’s most restricted air spaces.

A WSJ visual investigation breaks down the helicopter corridors, airport runway paths and light pollution that may have played a role in the fatal D.C. crash.

Chapters:
0:00 The plane crash over the Potomac River
0:34 The flight rules around D.C.
1:18 What happened during the crash
2:42 Air traffic control staffing and altitude