Rays of light from the sun filter around the limbs of a robotic sentry of some sort.

Another balcony shot overlooking the Traveler and the City; the speculation is that this is from the Tower, a safe area for players.

Yet another shot that blurs the line between concept art and in-engine footage.

This would appear to the the Citadel location shown earlier, referred to as a lair for bad guys. The environment appears to be Venus, but that's only speculation.

This is another one of those shots that makes it hard to distinguish between in-engine footage and concept art.

Across the landscape we get a closer look at the objects on the floor. They're clearly not natural stalagmites, although it's also not clear that they are (or were) figures.

Some semi-transparent tendrils seem to stretch over the area, looking like spiderweb. This shot reminds me of The Tain from Myth.

In the background we can see some arches that look like Forerunner structures.

Here we get a partial closeup of the restrained figure, including some of the detail on the cuffs. There appear to be banners hanging from the ceiling in several parts of the room, as was true in High Charity from Halo 2.