By the time it was done, Sunday night's attack had become the deadliest shooting in modern U.S. history. But when it began, all concertgoers knew was something felt very, very wrong.
Next week marks the five-year anniversary of the movie theater shooting in Aurora, Colo., that killed 12 people. Tom and Terry Sullivan remember one of the victims: their son, Alex.
"This must and will be a healing initiative," said owner Barbara Poma. It will commemorate the victims, survivors and rescue workers at the site of the deadliest mass shooting in modern U.S. history.
Over 20,400 pieces of gun-related legislation have been proposed in the past 25 years after mass shootings. Whether they tighten or loosen gun laws depends on the state's dominant political party.
Semiautomatic rifles like the AR-15 and SIG Sauer MCX, which was used in the Orlando shooting, are no longer banned nationally. States, though, are finding success in passing laws restricting them.