In a new set of photos taken on the set of Thor: The Dark World in Surrey, Comic Book Movie provides a look at a group of menacing, well-armed individuals assumed to be the film's villains, The Dark Elves.
Led by Christopher Eccleston's Malekith, The Dark Elves inhabit the realm of Svartalfheim, which is what this area (where a lot of shooting has taken place) is widely assumed to be. At this stage, there are so many Dark Elves there and so much battle going on that it's got to either be their home, or someplace they've conquered.
Worth noting: While The Daily Blam! notes that one of the characters is holding onto a weapon that looks like Item 47, the gun left behind by The Chitauri in Marvel's The Avengers, that's only partially true. There are superficial similarities, but it definitely doesn't appear to be the same weapon, so don't let that one image trick you into a "Thanos is behind Malekith!" theory.