their episodes and notably played the show-within-a-show directors in the cameo-heavy milestone episodes "Wormhole X-Treme!" and "200". Andy Mikita had been an assistant director since the pilot episode and directed 29 episodes from Season 3–10. SG-1 director of photography Peter Woeste and camera operator William Waring directed 13 episodes each. Most staff writers and staff directors held producer positions. Several cast members also contributed story ideas and directed SG-1 episodes. Filming Stargate SG-1 was filmed in and around Vancouver, British Columbia, mainly at The Bridge Studios and NORCO Studios, which offered Stargate SG-1 tax breaks throughout its run. The cost of an SG-1 episode increased from US$1.3 million in the first seasons to an estimated US$2 million per episode in Season 10, partly due to unfavorable exchange rates. Many Vancouver area landmarks were incorporated into the episodes, such as the campus of Simon Fraser University, which became the setting of the capital of the Tollan, an alien civilization. Production faced many weather problems because of the moderate oceanic climate of Vancouver, although rain could be eliminated from film. The Season 3 episode "Crystal Skull" was the first episode to be filmed on a virtual set. The main setting of Stargate SG-1, the fictional Stargate Command (SGC) at the (real) Cheyenne Mountain Air Force Station near Colorado Springs, Colorado, was filmed at stage 5 of The Bridge Studios. Martin Wood filmed half a dozen stock shots of the real Cheyenne Mountain complex for use in the series approximately ten days before the premiere of the pilot episode. Although these shots wore out over the years, the producers did not film new shots until the beginning of Season 9, thinking that Stargate SG-1 would be cancelled after each current year. By then, visitor questions and fan theories about the existence of a Stargate at the real Cheyenne Mountain complex had become so common that Cheyenne Mountain had installed a seemingly high-security door labeled "Stargate Command" for one of their storage rooms holding brooms and detergent. The first seven seasons had 22 episodes each, which was reduced to 20 episodes for the last three seasons. Episodes of the first seasons were filmed over a period of 7.5 working days, which decreased to a targeted average of six working days in the last seasons. All episodes were filmed in 16:9 wide-screen, although Stargate SG-1 was broadcast in 4:3 aspect ratio in its first years.