Parts of the show were filmed in Denver, Colorado and at the time the University Hills Mall was slated for demolition. For the mass destruction aftermath scenes, they used areas of the mall which had been demolished already and actually blew a few more things up themselves. Concerned citizens nearby thought the black smoke they were seeing was indicative of a real emergency and promoted over 100 calls/minute to 911.
The news scenes were filmed at the new NBC affiliate K*USA TV denver. KUSA had only been an NBC affiliate for just a little over a year, the producers used KUSA'S New News set to film the News Reports.