This Olympic flame is a fake.

Peer past daytime host Hannah Storm or prime-time host Bob Costas during NBC’s coverage of the Salt Lake City Games, and there’s no way to miss the fireplace on the well-manicured set.

Turns out, though, that the fire is not really there. It’s a video of a fire (replete with wafting smoke) that NBC tried its best to make look real.

“Our fireplace is truly one of the great mysteries of television,” NBC Sports VP Kevin Sullivan said with a laugh Monday, but he wouldn’t comment further.

It’s not, of course, the first time the wonders of TV have been used to trick viewers.

During its coverage of the Sydney Olympics two years ago, NBC wanted to minimize confusion that might have been generated by the 15-hour time difference between Australia and the U.S. East Coast.

So each night, the studio backdrop designed to look like Sydney harbor changed  through the course of the show, the sky went from early evening clarity to late-night darkness. In other words, lighting tricks were used to make what already was a fake backdrop even faker, giving viewers the impression the time of day in Australia was about the same as in the United States.

NBC isn’t alone when it comes to virtual enhancement in the name of aesthetics, here’s one other example from the world of TV sports:

In August 2000, a handful of bird enthusiasts watching the PGA Championship on CBS noticed some of the chirps they were hearing belonged to birds normally not found in Louisville, Ky., at that time of year. The answer: CBS was using recorded bird sounds for ambiance.