Here is a quick breakdown of what you need to know.
We later get a look at the villain Steppenwolf, who talks about how "this world will fall" without Superman. Then, all hell breaks loose and the team steps in to fight.
The buzziest part of the trailer is at the end. Alfred is doing what he does, tinkering on some Batman gadget when someone approaches.
"He said you'd come," Alfred says to the mysterious figure. "Now, let's hope you're not too late."
Is it Superman back from the dead?!
"Justice League" hits theaters on Nov. 17.
Hulk also talks for the very first time! P.S., Loki is back!
"Thor: Ragnarok" is out Nov. 3.
All the buzz wasn't just on the movie side this weekend!
As with other Netflix shows, there is a little cursing, so maybe check this trailer out after you leave work.
"Defenders" hits Netflix on August 18.
The "Stranger Things" kids are back!
Netflix also released the first trailer for the second season of the hit show, which returns in October.
It starts with the gang playing "Dragon's Lair," a classic video game, but then Will starts to have more visions.
"Nothing is going to go back to the way that it was, not really," an ominous voice says.
"Avengers: Infinity War"
Fans were already treated to a clip a week before at D23, Disney's yearly convention. But that didn't stop Marvel from showing the footage again at Comic-Con.
Also in this gigantic film are Spider-Man, Dr. Strange, Black Panther and many more!
Even though footage isn't online yet, there's key art from Ryan Meinerding, head of visual development at Marvel Studios, and it's glorious.
“Infinity War” is out May 4, 2018.
Editor's note: ABC News and Marvel are both part of parent company Disney.