I live just outside of Denver so frequent this airport. This documentary is pretty hilarious. I don't know what the horse is supposed to be, but I always saw it as being Miles, the Denver Broncos horse. I don't see anything bad about it other than it just being straight ugly. I've seen tons of tourists literally pull off the side of the highway, drive across the field, and hop the medians to take pictures next to that hideous thing.
The relocation for the airport was much more than nothing as the video states. Our old one, Stapleton, was very close to downtown Denver. It's a pretty populated area, and it's now a big shopping area. Denver International is way out in the open, so no one gets disturbed. I'm pretty sure it's much larger too, pretty sure it ranks up there as one of the larger airports. The land is much more in the open too, so when it snows they have tons of room to put the snow to which was a big deal.
No clue what the underground crap is though. My guess is it's storage and planning for potential expansions. The monorail that travels between concourses is also underground. Probably maintenance tunnels and stuff down there. The airport was located in the middle of nowhere with a huge emphasis on future expansion, so it's not far out to say they're for storage.
Pretty silly documentary, but an interesting find. DIA is really nice IMO, one of the nicest ones I've been too.
*edit* Oh yeah, recently they added some Egyptian statue. Apparently it's the God of the Dead lol. I've only seen it once the number of times I've gone there. It's pretty hidden and not that big. To that I have no clue what the hell they were thinking lol, but if I didn't hear the story I'd just think it was some Egyptian statue not the God of the Dead.
http://www.thedenverchannel.com/news/23778636/detail.html
Bahahaha, I just read the article fully. Apparently the blue horse statue fell on the creator killing him. Never knew that till now, pretty funny, sucks the guy died but a comical story to add to the conspiracy.