Risking death for thrills in Colombia - BBC News
"Gravity biking" is a popular extreme sport in the United States, involving riding specially-adapted pushbikes down steep roads.An even more extreme version ...
![Risking death for thrills in Colombia - BBC News](https://i.ytimg.com/vi/jrGFUFpJnk0/maxresdefault.jpg)
"Gravity biking" is a popular extreme sport in the United States, involving riding specially-adapted pushbikes down steep roads.An even more extreme version ...