The Great Wall of China runs for more than 4,000 miles -- or 5,500, depending on how you count the various connected and separate segments that have gone up over the last 25 centuries or so.
In this video, you get a good luck at one of the wall's busiest stretches: JuYong Pass (a.k.a. Juyongguan Pass), a sloping portion that's about 35 miles north of downtown Beijing. You also get a bonus: blue skies, a rare treat in an area with chronic air pollution. (I happened to arrive, in July 2013, on the day after a rainstorm.)