Everything you thought you knew is wrong. On almost every exterior shot you see on TV, the background is filled in via green screen. Watch this video and have your mind blown. [That's How It Happened via Kottke]
Consider my mind blown... and betrayed. Happy we live in such technomagical times.
... wait... there IS no stargate is there? All this time they haven't been filming on location offworld, it's been green screen all along?
So... who did I send my SGC application to...?