Nearly 7,000 athletes from 206 delegations were ferried down the Seine today in an extravagant and star-studded opening ceremony to kick off the Olympic Games in Paris. As the rain poured, hundreds of thousands of spectators cheered from the river’s banks. And Celine Dion closed out the night with a triumphant return to the stage.

The ceremony was a showcase for the city after years of planning. It continued as scheduled only hours after coordinated arson attacks brought France’s national rail system to a standstill, rattling nerves in a city under intense security. Here’s what we know.

Some competitions have already begun, but the Games move into full swing tomorrow with men’s basketball, tennis and women’s swimming (including the exciting 400-meter freestyle).

“Gymnastics, swimming and track remain the heartbeat of the Games,” Andrew Das, our lead Olympics editor, told me. “Good stories there will make any Olympics more memorable.”

Some athletes to watch are the gymnast Simone Biles, who pulled out of the Tokyo Games, and the swimmer Katie Ledecky, who is looking to add to her seven gold medals. France is also hoping for medal glory from Léon Marchand, a swimmer who is known as the French Michael Phelps.

Part of what makes the Games special, however, are the lesser-followed sports. Andrew recommended watching beach volleyball, rugby sevens and breaking, the new Olympic sport more commonly known as break dancing. There is also a bunch of under-the-radar American athletes worth following.