1. At first, it sounded like fireworks. This video shows the panic as it became clear that thousands of people at a country music festival in Las Vegas were under attack. Here’s our detailed account of the deadliest mass shooting in modern U.S. history, with at least 59 dead and more than 500 injured.

The police identified the gunman as Stephen Paddock, 64, and said that he had at least 20 rifles in his hotel room — including AR-15 assault rifles — and that the attack ended when he killed himself. There’s so far no clue about his motive.