"That is what we call a Stargate. It's a...sort of portal to other gates that are scattered around the galaxy. We use it to travel to other planets..." Time to let the cat out of the bag. "Which is where we found the buildings with the text I couldn't identify."

"This is the SGC or Stargate Command. You're actually under Cheyanne Mountain, the Norad project...or at least that's it's official purpose. Our project gets the much lower levels.
Sorry, this is probably alot to take in at once..."