Check out the following video which reveals an actual scene from The Avengers 2 being filmed on the streets of Johannesburg, South Africa.
We know the Hulk is involved as we've seen a prop featuring a Hulk head on set.
The following video may reveal Iron Man landing amidst all the Hulk-created destruction.
I believe in the upper left side of the following video that is the Hulk prop they have been using.
We see what appears to be the police or military having a confrontation with the Hulk as well as bystanders fleeing in the wake of all the destruction.
If you take a close look, we see there are about a half dozen of the police officers with their guns drawn at what may be the Hulk.
It then looks as if the Hulk might do a sonic clap as the prop gives off a loud sound with everyone hitting the ground.
Shortly after, take a close look at the upper left corner. We see a big cloud of smoke, with the police then turning their attention away from the Hulk (as it's a sonic clap, it just knocked them to the ground) toward whatever that may be (or just landed?).
It's speculated this is the opening of The Avengers 2 as a rep for the city of Johannesburg, South Africa previously let it be known the city would be featured in the first ten minutes of the movie.
"The Avengers: Age Of Ultron" hits May 1, 2015 directed by Joss Whedon starring Robert Downey Jr., Chris Evans, Chris Hemsworth, Scarlett Johansson, Mark Ruffalo, Jeremy Renner, Samuel L. Jackson, Elizabeh Olsen as Scarlet Witch, Aaron Taylor-Johnson as Quicksilver with James Spader as Ultron.
Head on over to the Cosmic Book News Avengers movie hub for more.
(images pictures from The Avengers movie)