The comment was in response to questions from Chinese people who e-mailed the television show's web site, asking the country's first man in space "to verify the popular belief that the Great Wall can be seen from space," as the news reports typically put it.

Most accounts left the impression that since Yang didn't see the ancient border, it isn't visible from on high. As the Associated Press put it, Yang "didn't see the Great Wall while in orbit, contradicting a Chinese belief that it is the only structure visible from space."

There are many variations on this myth, which dates to before humans put the first robotic satellite in orbit -- back when nobody had a clue what was visible from space with the unaided eye. One form holds that the Great Wall is the only manmade structure visible from the Moon. Another twist is that no manmade structures are visible from anywhere in space. And some people believe only the Great Wall is visible from Earth orbit, where Yang was.

Take your pick, they're all false.

No human constructs are visible from the Moon. But lots of manmade structures are visible from Earth orbit, including cities, highways and even some of the vehicles that traverse them. The Great Wall of China is visible from Earth orbit, too. Yang just didn't see it.

"You can see the Great Wall," says astronaut Ed Lu, the science officer of Expedition Seven aboard the International Space Station, which circles the Earth higher than Yang's path. But the Wall is hard to find compared to other objects. Long stretches of its thousands of miles have been covered by sand over the eons.

Yang's flight aboard a Shenzhou 5 was reported to range from 125 miles (200 kilometers) above Earth about 220 miles (350 kilometers). The space station is roughly 250 miles (400 kilometers) high.

Lu says he's been trying to take a picture of the Wall from his orbiting outpost, but so far weather hasn't cooperated.