Now that we know how zip lines work, why they developed, and the safety and accident risks, consider yourself ready for the zip-line trips you can take. These aren't the backyard lines your neighbor Jimmy rigged up; these are some serious hair-raising adventures for both fun and, as we'll see, work.
Costa Rica is an extremely popular destination for zip-line (or canopy) tours. Soaring above and through the rainforest, the industry has become one of Costa Rica's biggest draws.
Sun City, South Africa, boasts the world's longest and fastest zip line. Descending into a canyon, it's 280 meters (918.6 feet) high and 1,900 meters (6,234 feet) long -- roughly 1.9 kilometers (1.2 miles) [source: Zip 2000]. It supposedly reaches speeds of more than 150 kilometers per hour (93.2 miles per hour). But is it the scariest?
Consider St. Augustine Alligator Farm in St. Augustine, Fla., where one can fly blissfully through the air over the private enclosure of one 600-pound (272.2-kilogram), 13-foot (3.9 meter) Malayan Gharial crocodile named Mr. T. [source: Berry].
If you're looking for the ultimate zip line ride in North America, Coolest Stuff on the Planet blogger Amanda Arnold speaks highly of (if highly means she has a healthy fear and will forever avoid) New York Zip Line Adventures at Hunter Mountain, where the 3,200-foot (975-meter) zip line reaches 50 miles per hour (80 kilometers per hour), over a 600-foot (3.9-meter) valley. Depending what kind of person you are, that may or may not be worse than a 600-pound alligator.
And then there are the fun, utilitarian uses of contemporary zip lines.
Like some awesome school kids in Columbia who zip line their way from their isolated village to school every day. At a brisk speeds over 35 miles per hour (56 kilometers per hour), with a 1,300-foot (396-meter) drop into the canyon, these kids will pretty much beat everyone else's "walking both ways uphill in the snow to school" stories.
And then there's the real work of transporting contraband across national borders. In 2008, a smuggling gang in China allegedly rigged a 980-foot (298-meter) cable from a high rise in China into a village house in Hong Kong. Best of all? The gang supposedly used a crossbow to shoot the cable across the heavily guarded border -- putting to shame any mouth-breathing action heroes we've ever seen.
If you aren't already running to your nearest (safest) zip line, follow the links on the next page to learn way more about zip lines, the physics that makes the ride fun and other articles that will get your heart racing.