What Is a Zip Line?

I was wondering what is this zip line that everybody is talking about? Can someone tell me if this zip line is also known by another name?
I heard a girl who got flesh eating bacteria, fell from something called a zip line, I guess it's related to some sort of outdoors sport or something like that. Is it that thing where you hook yourself and slide?

A zip line (or flying box, or aerial runway, or many others synonyms) is a cable that allows you to travel along to places, usually used to access remote areas. For example, you can use it to "fly" to the center of a rainforest instead of walking. It is popular vacation activity and also an extreme sport. The zip line is very popular among the folks who go to the mountains often. So that's what a zip line basically is, if you have another question please let me know.